Chiptunes? Allow me to post some of my favorites:
First post, I'll leave you with Timothy Wright (also known today as "CoLD SToRAGE"). Much of the music he composed for games of the Commodore Amiga are very haunting.
For instance, here is this song that's worth sitting through the entire loading screen listening to:
http://www.youtube.com/watch?v=LV2Gafho8as
Another beauty that's worth loitering just to listen to the title song:
http://www.youtube.com/watch?v=X9UTnUcyED0
And now for music that are actually used in a stages of a game:
http://www.youtube.com/watch?v=eOSoYREc1CU
http://www.youtube.com/watch?v=6TmcaPUtvno
And songs from the game I shared the title song of:
http://www.youtube.com/watch?v=jQB3KZDeYQ8
http://www.youtube.com/watch?v=eg5sX1Yb0KI
Later, I'll share music from other favorites, such as Timothy Follin, Nobuo Uematsu (shut up, he has talent) and other composers.
Not going to let this thread die (even though it's been only two days without a reply) without mention of my all-time favorite composer for music in video games: Timothy Follin.
First, I'll post a two-parter of the entire soundtrack of The Commodore 64 port (though a pretty rough, rushed port) is pure gold:
http://www.youtube.com/watch?v=Kuv3SbWrsSk
http://www.youtube.com/watch?v=o5STzUDA9J0
And now, some of my favorites (The first post I had listened to for the first time today even), all cross-format:
http://www.youtube.com/watch?v=BHg14wwgtbY
http://www.youtube.com/watch?v=6OJIcDWaE3U
http://www.youtube.com/watch?v=ypNPxwnppU0
http://www.youtube.com/watch?v=3ODKKILZiYY
http://www.youtube.com/watch?v=GqyEbu8cmMg
^ What a shame the above game was never released, and that is all of what remains of it (for now).