The SIG P229 is my favorite: supremely accurate, totally reliable, feels great in the hand, very controllable during fast firing... looks good too. I like it so much I now have two of them
Video:
http://www.youtube.com/watch?v=es5xKKlIDwM&feature=user
I also like the HK P2000, for many of the same reasons as the 229. The P2000 is lighter though, so there is some trade-off in controllability during the most rapid of shooting... but this can be overcome with lots of practice and lots of lead down range. P2000 would be more comfortable to carry.
I also have a P7 PSP which I like a lot, and I have a SIG P239 TAC arriving any day now (hopefully tomorrow!!) and I am also building a mutant SIG 228/Norinco NP-34 which I will be showing you guys a lot more of in the coming weeks. It could turn out to be the best $500 gun around.
Not bagging on anybody's favorite here, but 9mm guns that I used to have and have since sold for whatever reason: GLOCK 17, Steyr M9-A1, Steyr GB, Walther P99 AS, HK USP.
Nines that my girlfriend has or has owned that I have shot alot: Beretta 92G (her old gun), Beretta 90-two (her current gun).
Nines that friends have which I have shot that I can think of off the top of my head: SIG 210, 228, 226, GLOCK 19, HK P7M8, CZ 75, Baby Eagle, S&W M&P, Grand Power, Norinco NP-29, other 9mm 1911's, Browning High Power... I'm sure there are others that I can't think of right now. Suffice to say, I have tried a good selection of what is available in nines, and the 229 and P2000 are right up there.