Turrican 2 +1, the only Amiga game music in regular rotation on my mp3 player. Really awesome!
Cannon Fodder too.
Also I know it's mostly licensed (is it?) but I love the music in Frontier, a true space opera
Speedball 2 loader tune captures the theme of the game perfectly.
Simon the Sorcerer 1, ah, nostalgia...
XP8 intro tune
and many many more I can't remember right now..