Mega Man, Initial D, Street Fighter, FF Series, Castlevania, Gain Ground, Dynasty Warriors, Chrono Series...

...too many to name, anyone else?

Dynasty/Samurai Warriors
Lunar Series
Shining Force Series
Street Fighter series
Sonic the Hedgehog series
Super Smash Brawl
Final Fantasy 1, 5, 7
Edit: Forgot Gain ground

These are probably the ones that I can listen to most of the soundtrack and like. I would listen others but I only like a select few of them such as Chrono Trigger or Starfox.

I love everything by Nobuo Uematsu and Yasunori Mitsuda.

I dig a lot of the 8-bit stuff as well. Megaman, Castlevania and Mario being on the top.

Street Fighter 2, Romancing SaGa 3, Last Blade 1 and 2, Okami, Medieval 2: Total War.

Final Fantasy Vocals and Street Fighter mainly. I'm starting to lke HACK GUI.

I always liked the techno soundtrack from the original House of the Dead on the Saturn.

i LOVED the bgm for Tekken 2, Kingdom Hearts 2 , and FF 10 , Chrono Trigger, and the ominous bgm for the original Resident Evil all come to mind

oh yes! and KOF 200!

Is it wrong to say all the DDR games

9 times out of 10 I turn the music off or all the way down in the options. and I've never come across anything I would want to listen to away from video games.

I cant believe nobody here has listed Yuzo Koshiro yet! He's the man behind such musical masterpieces as the Streets of Rage series and Act Raiser. He also did Revenge of Shinobi and is one of the japanese gaming godfathers behind the development house called Ancient. I'd recommend checking out the heavy metal remix stylings of his works done by Brazilian metal group Megadriver. They did a whole tribute album called Swords Shuriken and Fists, available for free directly from the band's own website.

http://www.megadriver.com.br

We also cant forget the legendary Koji Kondo, who has composed the major themes for almost every major Nintendo franchise since the original Super Mario Bros. While his tunes may not pump you up, you certainly cant forget them. I know I for one have the overworld theme music for SMB1 and 3, Zelda, and Starfox 64 permanently burned into my skull.

I think one of my favorite soundtracks as of late has been the Mother 3 soundtrack. It fit the mood and style of the game perfectly while remaining reminiscent of it's predecessor without outright copying it. It's actually amazing how much of an effect a soundtrack can have on a game. I think a great example would be Yoshi's Island on the SNES, that game had an outstanding soundtrack that almost made the game worthwhile on it's own. The DS sequal on the other hand was virtually a direct sequel - preserving the artistic style and basic game play, but they completely ruined the soundtrack and that really killed the game for me.