Nice choices!
Mine was a difficult decision between Rob Hubbard and Martin Galway; Hubbard's track for the game 'Thrust' is amazing, and some of the sounds he coaxed out of the Sid chip still sound great, but for me Martin Galway's melodies have the edge.
Check out this site;
http://www.tdubel.com/emulaattorit/sidmt.htmlIt's in German (I think) but there's a couple of tiny downloads of some of the best of Galway and Hubbard which can be played through Deliplayer (deliplayer.com), including Galway's brilliant Ocean Loader track, and Rob Hubbard music for Thrust. Invest a bit of time to see where it all started!
On the Amiga it's Bjorn Lynne (aka Dr Awesome of Crusaders), followed by Bruno (wrote some amazing jazzfunk tracks), 4-mat and Jester.
I agree with you about modern games; some of them do have great soundtracks (eg Outcast, the GTAs) but for 'proper' computer music the last bastion is probably the shareware/independant scene.
Steve