For me, it's first-person shooters with the exception of the Metroid Prime series. I can't really put my finger on why, I just don't enjoy them as much as some of my friends do. I'll play them (Battlefield 1942 was a huge time-consumer during college, as was Quake 3), but I generally don't get into first-person shooters.
Realistic sports and realistic racers. I feel like, by trying to match a specific, real thing as close as possible, they greatly limit themselves. If you have played one or two you have basically played them all.
I enjoy FPS, but I never get very excited about them. I tend to only enjoy them in a casual manner, for the co-op (though Bioshock was pretty cool).
The strategy RPG. I've gone at length on why I can't get into them before, but to sum up: I think the "rpg elements" screw up the "strategy" part completely. Couple that with opaque mechanics you need that require a guide to figure out, and long-ass campaigns (which isn't conducive to experimentation) and you've got something I just can't get into.
Sports(not motor sports) and Real-Time Strategy games...no exceptions.
I just don't find professional sports that interesting enough to want to play a videogame version. I can't get into RTS because I like to take my time to plan out stategies and I can't do that when it's in real-time.
First-person shooters. Don't like 'em. Although I'll admit aiming with the Wiimote has made things much easier for me to handle the gameplay. Still, that particular genre is boring to me overall. Not a fan. Also...
Sim-style racing/driving games. Driving around slowly, with sticky turns and boring cars (that you HAVE to drive first in order to get to the good stuff) just isn't my cup of tea. I like my racing games fast and over-the-top. More Rush 2049, less Gran Turismo. Gawd, those sim-racers really put the "B-O" in "BORING" in my humble opinion.
Outside of those? I'm actually pretty accepting. Even within those genres above I've found exceptions to the rule, with games I've enjoyed (but didn't love). But if an FPS or sim-racer come out, my care cup is already half-empty, if not completely empty, lol.
Yeah, I looove strategy games. And I love Advance Wars, which is decidedly purely a strategy game. The only game of the series with RPG elements in it, Advance Wars DS (experience points and leveling up your CO), is kind of unbalanced, which only supports my point about the RPG elements screwing up the stragegy element.
I dunno'. I rather enjoy the combination of the two, depending of course on how the game plays. NIS, to me, tends to strike a really interesting position between the two, and offer different "levels" of involvement (you can run through them rather quickly with minimum knowledge... or be completely OCD and fight everything up to a Level 6000+ final final hidden final boss). And for the most part, they tend to not take them seriously.
FFTA (can't speak for the second one, didn't put any time into it before selling it - now as predictable as it seems, I want it back, lol!) I thought did really well also.
Though it is true that you can make your squad extremely powerful and run over pretty much anything in the game after that.
EDIT: The blue is the portion I somehow didn't type before posting, lol. Oops!
RTS games. (No exceptions... unless you want to count Pikmin as an RTS, which I don't.) Hate having to direct lots of people to different stuff. I'd rather take direct control over 1 person than direct 100. Realistic sports games. (No exceptions.) As boring as the sports themselves. Realistic racing games. (No exceptions.) See above. "Underground" racing games. You know the type. (No exceptions). Such a... nauseating culture. Western RPGs. (Exception: Fallout 3.) Too many dialog trees and stiff animations and NPC interaction and other boring stuff I don't care about. Pretty sure only reason I like Fallout 3 is because it's first person and post-apocalyptic.
I THOUGHT I would hate strategy/tactical RPGs because I hate RTS games, but I ended up loving the Fire Emblem series and Shining Force II.