Which to pick? There are too many.
Zelda has such beautiful music, especially in Skyward Sword where they used real instruments. I LOVE Gerudo Valley, Dragon Roost Island, and almost everything from Skyward Sword. I could go on and on about the 25th anniversary album but I won't.
Final Fantasy music is just...... ugh. Amazing. Especially the theme from 10 and everything from 7.
I enjoy some of the soundtrack for FIFA '12.
The theme from Halo is pretty awesome.
The Binding of Isaac has a really cool theme.
I like the old school Mario songs, they're awesome.
The Donkey Kong theme YES. And Gangplank Galleon or whatever.
And that one Megaman theme that everyone and their mother uses in IWBT___ fangames.
.......................I could go on and on and on. I love music.