There have been a lot of games but few of them have original music that I can still remember today. 

These tunes are so powerful in my memory that sometimes I even break out and hum them out load. 

I have decided to make a link to some Youtube ones that I can find.  If you want you can do the same.

Medal of Honor main theme
http://www.youtube.com/watch?v=-ELFxB-tGhE

Diablo Tristram Village theme
http://www.youtube.com/watch?v=Q2evIg-aYw8
other version I like
http://www.youtube.com/watch?v=n0rvuaDPJgo

Mario
http://www.youtube.com/watch?v=MEKDF_WbMlg

Final Fantasy
http://www.youtube.com/watch?v=FQwAxMiKHPo

Dragon Quest
http://www.youtube.com/watch?v=__BiCY6tyZc

Legend of Zelda
http://www.youtube.com/watch?v=UOa4tXG4EQo
other version i like
http://www.youtube.com/watch?v=-MTWIjzjBSY

hope you injoy.