I used to be REALLY into fighting games a few years ago, but now I just try to focus on all sorts of classic gaming.
My all time favorite fighting game is The King of Fighters '98, mainly because of the hardcore, technical, in-depth gameplay and the huge character list. When it comes to the playability, this game is pretty much as perfect as it can get. Characters are balanced extremely well, tons of manuever variations, a flawless amount of different moves, an excellent combo structure, etc.... Besides the gameplay, it's not really a "great" game, but that doesn't matter because the gameplay is near perfection.
My favorite KoF characters: Benimaru, Yamazaki (ultimate fighting designed character in any game), Kyo, Ryo, Saisyu, Takuma, Athena, Kensou, and even Chizuru (who most people HATE). Pretty much every character is good in this game because it's so well balanced.
Other favorite fighting games of mine:
Street Fighter II (specifically Super Street Fighter II and Super Street Fighter II Turbo), SNK vs Capcom: Match of the Millenium (Best pocket fighting game out there. Simply amazing!), Fatal Fury Special, Street Fighter Alpha 3, KoF'97, KoF'2k2, KoF'2k1 (Well sort of. I just like going into practice mode and pulling off huge combos with the strikers and infinites), Last Blade 1 and 2, X-Men vs Street Fighter (The only game in the Marvel vs Capcom series that I like. I can't stand some of the others.), Garou: Mark of the Wolves (Well this game is both good and bad to me.).
Favorite Street Fighter characters - Guile, Ken, Zangief, Guy, Rolento, and more.
Fatal Fury Special - Jubei, Geese, Duck King.
SvC: Match of the Millenium - Zangief (Zangief plays amazing on the NGPC click stick. You can combo in his throws with no problems!), Kyo, Ryo, Iori/Evil Iori, Ken, Bison (even though he is a bit cheap).
Last Blade - Moriya (similar to Yamazaki, only not quite as awesome), Lee Rekka, Kaede, that ninja dude (forgot his name, been awhile since I have played these games), Kagami.
XMvSF - Haven't played this game in a LOOONG time, so I forgot who my top tiers were. I believe Ken, Gambit, and Wolverine were characters I enjoyed using. Charlie too, of course.
Garou - Rock Howard (Awesome character. Nothing cooler than Geese mixed with Terry), Marco Rodriguez (Or "Butt", hahaha.), Kim Jong Il (or maybe it was the other Kim-like character).
Fighting games rule, but they can be pretty deadly in real life and cause some actual fights, which is another reason why I don't play them as much I used to anymore
. Competition can get brudle. One time I was wipping my cousin's ass in KoF'98 so hard (like a 20-30 win streak) and he was getting so pissed off that he actually CRIED, hahaha. That felt really weird for me.
Do you have a fast connection, Ninja Spirit? Maybe we could play some of these games on Kaillera sometime.