Since other folks seem to have covered the non-standard skills the OP brought up*, I'll go over a few which I've tried out over the...
decade and a half since I started playing this game. Wow.
Big Guns - I know Pawka said s/he's tried this. Nevertheless, it took me a long time to get around to playing the character whose strengths worked this direction. Speaking mostly of Fallout 1, they're inefficient, but they're fun.
Throwing - Oh god. Avoid this. In either Fallout 1 or 2, it is the worst of both worlds. No perks make it practical, not even Slayer or Sniper as neither applies, and it is the art of throwing your weapon away from you. If you want a tedious (thought possible) playthrough, I suppose you can try it out. Challenge games should be interesting, though, not boring. And no, the grenades just aren't any real good in my experience.
Doctor - This is often in my top tier. Taking First Aid as a TAG skill makes little sense, but Doctor can't be trained up most ways and places, and leads to interesting plot points in Fallout 2. Additionally, it's an easy source of experience and cheap health, and there will be time you'll break your bones. Or have your eye gouged out. (Ick.)
Lockpicking - There's a limit to how high this must be before it's universally applicable/useful, but that limit's not especially low. A bad choice for a TAG skill, but a bad skill to neglect as well. Especially if you're sneaky.
Repair - Can be trained as high as needed with books. Probably a good idea.
Traps - To be honest, I've never bothered. I should try it some time.
Science - This is one of my big three more often than Doctor, as it seems to make the world go 'round whenever Speech doesn't. Computers, conversations, or even end-game dialogue can be shaped by your knowledge of this skill.
Gambling - Tedious as well, but an easy way to get equipment you'll otherwise miss entirely. In Fallout 1, bringing this skill above 50% (maybe 65% or more for good measure) this allows you to loot the Hub for decent gear in a remarkably short period of time. It's a long process, but given that the sequence wherein you'd obtain this gear is only applicable if you're playing a bad person, this is a solid way to get very decent equipment early on, with or without being on the Brotherhood of Steel's good side. It is reliable (ironically.) It's also boring. But boring can be okay if it's for a good cause.
It's also disturbingly powerful for using books to increase your skills. That librarian charges high prices. As such, it can be a gateway to getting other skills quickly to 100% or better. (You see, it's also very, very good for buying drugs.)
Barter - I would say this skill is mutually exclusive with Gambling. Either you're getting your money by spamming the slots, or you're selling everything you find as high as you can. Mind you, it's not so much that Barter effects your selling price. Short of non-skill-related factors, a suit of leather armor is 800 caps/bucks and nothing much changed that. However, that Super Sledge on the shelf may suddenly become an achievable goal when you knock off 50% of its price or more. And hey, if you want to keep developing this skill until it's at full, you'll have more caps/bucks than you could ever imagine what to do with. Which does get a bit absurd, really.
Outdoorsman - Incredibly convenient, and necessary for character who need to pick their battles. Making it a TAG skill seems like a bit of a waste, since you can get 91% even without using drugs to screw with your stats. Still, buying the books will take a while (unless you're a Gambler.)
I've seen worse choices for TAG skills despite that factor, and always bring this up at least to 100% regardless.
In Fallout 1, you can traverse huge stretches of map without combat. This is just plain nice. It's not a big map, to you get to know it. It's like a friend or a lover, not an enemy you must subdue or escape.
In Fallout 2, you can actually and deliberately pick your battles this way, deciding on any given occasion whether you really want to fight those geckos or just walk away.
I hope this was helpful.
* Including the fact that two out of three of them are, for me, very standard
Post edited March 26, 2012 by MackieStingray