My experience with other classes is certainly not extensive enough to be able to say this with complete surety, but it seems to me that hunters, more so than other classes, are very spec-specific. Think of your average Joe R. Hunter (where R stands for "raiding") and think of his probable talent spec. 41/20/0, 0/41/20, 0/20/41, 0/31/30. Maybe a coupla 40/21/0 and 0/21/40 thrown in for Scatter Shot and good measure.
Now, this definitely isn't to say that there aren't other good specs out there (in fact, I'll address that at the end of my post) but this seems to be what you will see, most of the time. It just seems like that typical end-game hunter strategy is to grab those 20 key points in the Marks tree and then spread from there. I think, however, that what you do with your other 41 points (or even those "key 20 Marks points") can really vary depending on personal preference and what you want.
Here, I'll use my own current spec as an example:
Let me talk about what I've picked and why I've picked them, and why my overall talent spec is largely personal preference... and probably different from your personal preference.
Pretty standard cookie-cutter 41/20/0 build at first glance. Typically considered by most to currently be the highest DPS hunter spec in the game, although there are a lot of disputes about whether or not this is actually true, especially when really, really nicely-geared Marks or Survival hunters are involved.
I personally chose Beast Mastery because I find it appealing from an emotional and aesthetic standpoint (geeky, no?); the DPS bonus is some very tasty icing on the cake though.
5/5 Improved Aspect of the Hawk: Has a chance to increase your ranged attack speed by 15% for 12 seconds. This is awesome. It's like squeezing bonus ranks out of Serpent's Swiftness. Obviously this is proc-dependent so it's not always reliable, and if you prefer to run around with, say, Aspect of the Viper up, then this might not be such a good choice for you. But overall I see this as a must-have for me. (Little secret: I am madly in love with the little WHOOSH noise that it makes when it procs and the little picture that pops above your head. That's another big reason I always take this talent.) Warning: there is the possibility that it will mess up your shot rotation, but I've never had an issue with this.
2/5 Endurance Training: Yeah it's maybe a little silly to have these two points here, but I still do a lot of grinding and stuff-- with DPS pets, no less-- so they can use all the staying power that they can get. Note: In my little opinion, 5/5 in this talent is pretty much mandatory for leveling. All my leveling hunters get 5/5 Endurance Training; they can respec later.
2/2 Focused Fire: 20% Kill Command crit is amazing. That's really all I have to say about that.
2/3 Thick Hide: See my comments for Endurance Training. Again, I would recommend a full 3/3 for leveling BM hunters.
5/5 Unleashed Fury: Increases your pet's damage output, pretty straightforward.
2/2 Improved Mend Pet: A lot of people I know do not put points in this and I have to admit it sort of baffles me. I don't think I could live without this talent. This is one of the things that got me to respec from Marks in the first place. Picture this: You're attacking something and your pet gets Faerie Fire or some other debuff that completely demolishes their armor/stamina/attack power/whatever. Whatcha gonna do about it? ...Improved Mend Pet, that's what! Oh, and the mana cost reduction is fantastic too.
5/5 Ferocity: Increases your pet's crit. More pet crits = More Ferocious Inspiration for you (er, for me, anyway). This one's a given.
Intimidation: This is the "Who comes to the rescue when the tank falls down" talent, to quote a line from Hootie the Strigid Screecher. Is your pet a replacement for the main tank? Oh, heck no. But if the boss a five-man is getting to end of his rope, something happens to the tank, and it's your pet or the healer-- this is when your pet comes to the rescue. Usually the healer realizes that your pet is the new tank and will plant enough heals on him to, if things go well, finish off the fight. Locke has successfully tanked both the last boss in Hellfire Ramparts and the last boss in Escape from Durnholde Keep in this fashion. Oh, and this talent is of course the gateway for some awesome talents down the road.
1/2 Bestial Discipline: One of my big personal goals is to have Ferocious Inspiration up 100% of the time. One of the ways I achieve this is to dump a bunch of focus onto my pet, so he has more chances to use Claw, which will hopefully crit. At this point in time, my crit is high enough that when I'm completely buffed and ready-to-roll, I can usually keep Locke or Tux full of focus with Go for the Throat, but there are always those long "droughts" where you won't crit for a while and 1/2 Bestial Discipline helps act as a safety buffer. Note: I would seriously consider going 2/2 here if I were using a Windserpent or something, because of Lightning Breath (costing more focus than Claw).
2/2 Animal Handler: This isn't quite so important pre-level-70, but basically this is your only way to increase your pet's chance to hit, which is going to be very needed in harder instances and raids. More hits = more chances to crit = more guaranteed Ferocious Inspiration.
4/5 Frenzy: Makes your pet attack faster. Again, more hits = more chances to crit = more guaranteed Ferocious Inspiration. You may have noticed I only have four points in this talent. A lot of hunters do that. I'm not one who's much for math or theorycrafting myself, but I do recall reading somewhere that 4/5 Frenzy is just as good as 5/5 Frenzy and in my experience that seems to hold out to be true. I love having an extra point to play with, so 4/5 it is.
3/3 Ferocious Inspiration: This is one of my very favorite talents and I put a lot of hard work into spec'ing myself and my pet so that this is up near-continuously. This increases the attack power of everyone in your party by 3%, and this works on melee, ranged, and magical attacks. 3% may not seem like a lot, but it adds up. And I just love the idea of it.
Bestial Wrath: This is a given; who doesn't want to watch that big red pet doing almost as much DPS as you while being immune to most everything?
5/5 Serpent's Swiftness: I think this is possibly the talent that makes BM the powerhouse spec that it is. This is what defines the BM shot rotation (Steady Shot/Auto Shot/Kill Command) and allows us to out-DPS a lot of Marksman hunters who are hitting harder, but slower. So... yeah. This is a given.
The Beast Within: Some people prefer Scatter Shot; myself, I like having what is almost the equivalent to a "second PvP trinket". This is the Warlock-buster. Oh, and the Warrior's hamstring/Rogue's poison/etc.-buster. =P
For the most part, you will see these 20 points on pretty much every end-game hunter. There is one debate though, that I will get to in a second:
5/5 Lethal Shots: Crit is good.
5/5 Improved Hunter's Mark: This is where there's a divide. A lot of hunters-- most, I think-- would rather have 5/5 Efficiency. Myself-- I'm an Improved Hunter's Mark fan. What it does is buff the melee attack power of everyone who is attacking whatever you've marked, whether they're in your party or not. This buffs your pet and it buffs anybody who uses melee attacks. I have always been one who enjoys helping out the party as much as I can, and being able to provide a 110-attack-power-bonus to people is almost like having my own little Trueshot Aura. Also, I have never been in a situation thus far where I've wished I'd taken Efficiency instead. I know, I know, a lot of you are probably saying "Just wait until you start raiding!" And I understand that, and if the need arises to take Efficiency instead, then I will. But at this point I haven't needed it. I would rather be buffing the attack power of my pet and the tank and the rogues and other hunter's pets and the feral druids, than giving myself a few extra Steady Shots before I have to pot. But that's just me. =P
2/2 Go for the Throat: This generates a lot of focus for your pet and in my mind is a must-have talent.
Aimed Shot: I really only use this against healers in PvP (paladins mostly), but it's the prerequisite for another awesome talent.
Rapid Killing: The best place to toss those two extra points you need in this talent tier; it gives you a little boost if you are killing things quickly and shaves some time off of the gigantic Rapid Fire cooldown.
5/5 Mortal Shots: Increases the damage that your crits do. <3 big crits.
Well, there you go. That is why Pike specs the way she does. It's not a perfect spec. But it meeds my own personal needs, and that is what talent specs are supposed to do-- fit an individual's needs. This is why I don't think there is "one spec to rule them all", and this is why I make an effort not to judge somebody based on their Armory profile.
Lemme tell you a story quick, and then I'll let you go, since this post is long enough already!
One of my friends has a level 70 hunter alt. Because this hunter is an alt, he's not all that geared. He has a level 64 green helmet of the Bandit; he has Valanos' Longbow without the scope and overall he's just in quest gear. He has a solid but not exactly cookie-cutter BM spec.
Guess what happens when he, I, and another hunter in Season 1 PvP gear all go into battlegrounds? Guess who, without fail, tops the damage done and the killing blows and the honorable kills at the end?
I'll give you a hint. It's not me. And it's not Season-1-gear-hunter either.
It's Mr. Green Helmet.
He is the only hunter I have played against so far who can beat me in a 1-on-1 hunter duel up to about five levels higher than me (that is to say, other hunters who attack me on my RP-PvP server hordie, cannot beat me unless they have over five levels on me.)
The last time we dueled it was in the Stranglethorn Arena to make things dramatic, and we had a little guildie audience too. There I was, completely decked out in blues and purples and with everything enchanted to the brim. Savagery on my Sonic Spear and +10 damage on my Gladiator's Heavy Crossbow. And there he was in quest blues and greens.
He had about 100 hit points left when I fell. He told me afterwards that if I'd used Serpent Sting, I would've won. And he's right. But the fact is that I failed to use Serpent Sting and thus he won fair and square.
I haven't a clue how he does it. Somehow he manages to work magic in PvP. He's told me he feels much the same way about me in PvE, he says he doesn't think he could ever pull off what I do in instances. This is very flattering, but it still completely blows my mind that he's working his magic in quest greens.
The hunter I have the most respect for isn't some T6 hunter with Illidan on farm. The hunter I have the most respect for isn't in complete season 3 arena armor with some incredible rating. No, the hunter I have the most respect for is wearing a green helmet of the Bandit and only has one point in Frenzy.
Armory profiles aren't everything. Gear isn't always everything. Spec isn't always everything. You spec the way that is best for you, because you know your playstyle the best. The results may surprise you.