Just a couple games I;ve been playing recently:
Jamestown: Legend of the Lost Colony.
http://www.youtube.com/watch?v=iDk2Cpc_0Mg
The whole soundtrack is amazing. When I'm not making music, I'm usually playing any Shmup I can get my hands on. Jamestown has to be one of the best I've ever played and a big reason is the epicness of the soundtrack. Playing with a friend (or 3) is even more epic expecially when you're familiar enough with shmups to survive on harder difficulty levels.
Castle Crashers (xbox arcade) has a damn good soundtrack as well. It's freaking enormous.
http://www.youtube.com/watch?v=tMQMktHB
ure=relmfu
Beating the piss out of your buddies to get to be the one to kiss the princess with that song pounding in the backround it probably one of the most fun things i've ever done in a videogame.