The whole of the Ace Attorney series has amazing music, specially Justice for All and Investigations.
Also, Layton, as Marche posted, has some of the best soundtracks I've heard, yes. There's also Mario, Zelda, Metroid, Kirby (oh God Kirby... so good)... and some lesser appreciated ones, like Rhythm Heaven's (some are annoying, but most of them are gold), Punch-Out!!, Kid Icarus...

And as for standalone themes, Korobeiniki is definitely one of the most addicting themes ever.

Katamari music

StarFox , Sonic, Super Mario, Metal Gear Solid, Ace Attorney and Super Smash Bros are the main franchises on my MP4 (yeah, MP4s are from the past century, but hey... those are very versatile...).

95% of the music I hear per year are from games.

MP4's are outdated?
I must not be up to speed with modern technology most of my music is from MP3 players I wasn't aware we had beyond MP4.

Well, MP14's already exist, then, MP4's must be very outdated by these times...
However, MP14's aren't so much different from MP13's, MP12's, MP11's and MP10's. Understand the new technology is a difficult, annoying thing. XD

O_o. Yeah I only know MP3. MP4 is video? I didn't know we are up that far(14).

Maybe MP6's and up are just Korean copies of the rest with one different function.
Here at Brazil we have a expression for these modified copies: Xing-Ling.

there are ofcourse the classics liek Megaman but some companies took the big step and got entire orchestra's hin hint Metal Gear Solid. Soem soundtarcks are just awesome compliations - Brutal Legend.
But oe of my favourites is teh soundtrack to Modern Warfare 2; seriously it was by HANS ZIMMER! He's legendary for movie soundtracks. great scale of epicness

Why? It's a pretty sweet game!

I kinda feel noobish here, but what game are you talking about?

My favourite video game soundtrack is from Xenosaga Episode 1 - The game over theme was so sad, I loved it. Here is a sample:
http://www.youtube.com/watch?v=5fJID87z ... 1&index=42
It's so beautiful...

Absolutely. Just about anything Mitsuda composed made other video game soundtracks sound like pop music.

I almost cried when he didn't return for Xenosaga Episode 2. Then I almost cried again when I heard the crap that had been composed instead. And when I say crap, I don't mean "because it wasn't Mitsuda." It was crap. Really, really crap. In the first game, the cities and colonies had no BGM. Looking back, I would have preferred it to this crap. Fortunately, the composer got a clue and gave us a soundtrack to the third game that could probably rival Episode I's.

I picked up A Copy of The Complete Megaman Zero Collection and remembered why I loved it..

Woah, woah, woah, you neglected to mention New Destroyman, Captain Vladimir, Alice Twilight, Cashmere Cannonball, NO MORE NO MORE HEROES, and The Virgin Child Makes Her Wish Without Feeling Anything?

I've come to realise that 's sounds a lot like the music in the Legend of Zelda ;D Especially Spirit Tracks.

Woah, woah, woah, you neglected to mention New Destroyman, Captain Vladimir, Alice Twilight, Cashmere Cannonball, NO MORE NO MORE HEROES, and The Virgin Child Makes Her Wish Without Feeling Anything?

Yeah, Pokey and DoMaya are pretty much the same person.

I've come to realise that 's sounds a lot like the music in the Legend of Zelda ;D Especially Spirit Tracks.