Yo MD-4/8 people:
Whenever you buy or whatever, get at least 8 tracks; bouncing is all right but then you only can control the volume of the bounced tracks; putting each sound on a single track lets you tweak THAT PARTICULAR SOUND to your liking and the end result is much better than bouncing, as you can tweak reverb/volume/eq/etc.
I've noticed that a couple of new units out there by Akai and Fostex have gone to 12 tracks. Well, for my use, 8 tracks have been enough but the lure of four more tracks is interesting. Whatever you need is certainly available.
Have fun.
Green Hornet