Normally, I try to stay out of "personality pimping" threads, but in this case, I'll bite:
I like 2D and rail shooters, mechanics-heavy RPGs (especially PC RPS and SRPGs), racing games, fighting games, turn-based 4X games, PC RTS titles, and any FPS that isn't badged with the Tom Clancy name or has pretensions toward military simulation. I appreciate strong iconography, clever abstract design, orthodox mechanics wed to unorthodox style, and a strong emphasis on the mathematical component of gameplay.
I tend to avidly dislike immersion, anime storylines, cutscenes, context-ignorant controls, mini-games, military/urban fetishism, simulations of any variety other than rally racing (a weird preference of mine), a silly overemphasis on "realism", and innovation for innovation's sake.
The games I prefer almost always devalue immersion in favor of strong mechanics, or have a sufficiently complicated system to make the cutscenes and plot more bearable. Currently, my favorite games range from old-school shooters like the R-Type and Gradius series, to the Nippon Ichi strategy RPGs, to the Zelda titles, to PC offerings like Diablo 2, Shadow Magic, Kohan AG, and Disciples 2.
I'm indifferent on most of the popular titles because most don't fit my tastes. I dig Halo 2 a lot, granted, although the SP cutscenes really wore on me -- thank God I could skip 'em. I might give GTA:SA a shot if/when it hits Xdude. MGS3 -- I can't stand the scenario design, the controls, or the mechanics of the series, and while I appreciate the post-modern pretention of the series, as ironically earnest as it is, I don't think I could stomach another after meandering through the second MGS title (on PC). I always THINK that I'll enjoy emergent games like Morrowind, The Sims, or other "sandbox" titles, but they always wind up being too shallow and too reliant on an idea of immersion rather than providing real challenge. Fable worked for me because it was over before it wore out its welcome. Nintendo games were classic back when they defined genres -- I think Yoshi's Island is the most sublime 2D platformer ever made -- but outside of the Zelda series and Pikmin 2, their recent offerings have left me cold. (Well, I enjoyed SMS, but it also had a lot of wasted potential.)
I absolutely HATE the survival horror genre as well as the generic mascot-driven action adventure so popular these days. "Stylish action" is also becoming very tired, although I dug Otogi 2 just for the lush visuals and stellar score.
The short version: I'm an old C64/Amiga/PC gamer who played consoles only as an alternative to his beloved computer games in high school. I had a Nintendo, but it didn't really blow me away -- it had ugly graphics/sound (by an Amiga fanboy's standards), and it didn't host the nerdy RPGs and turn-based games I dug. I never became a console fanboy because I never had a favorite console, despite owning a TG-16, a Genny, and a SNES in college. I've always bought a console because it had a specific game I just *had* to play, not because of the name or lineage of the hardware manufacturer.
Me and MAF are not the same person despite what the local Art Bell crowd would have you believe, and we actually have pretty distinct tastes. MAF lives near me, and we hang out a fair bit -- and occasionally send each other links to "interesting" threads over IM or #ga -- but any of the folks who know us (Shouta, kiryogi, Frag) will recognize that while we have a lot of overlap in taste when it comes to fighting and RTS games, we also have a lot of differences of opinion. He digs BF1942 and online FPSes; I don't mind watching 'em, but I don't feel any urge to play 'em. I play more "nerdy" PC 4X "bearded man" games which probably bore him to tears. I also play more RPGs than he does, and he values a quirkiness of theme more than I do.