Up until now, we have been version strict about using music that can played on Commodore 64 hardware. This can be a double edged sword, as it's hard to make this music sound palatable to modern ears, but if we can, there is obvious kudos to work within the limits of old technology. So what are your opinions? Should we relax this a little bit? Keep strict? Do an alternative soundtrack option like Cave Story?

All SID all the time! :D 

I'd stick with SID

I'd suggest to make retro-styled songs.

I guess it will be more pleasing to most listeners and it if it makes work easier for you, then I can only see advantages.

You could always "remaster" your sound to a c64 style later on and give the users the option to switch between the 2 sound-modes.

SID would deepen the whole aesthetic effect IMO. 

I dig what I have heard so far!  I especially liked that clip that showed the sunset and then there was music with it.

SID needs more love, but I'd be okay with an alternative soundtrack as well.