This one gets asked all the time, and should be made a sticky here IMO
PC SF editors:
Kenneth Rundt's - Viena, Free, http://www.saunalahti.fi/kru99/Downloads.htm
Creative Labs - Vienna, Free (requires creative soundcard), http://soundblaster.com/soundfont/downloads.asp
FMJ Software - Awave Studio , shareware, full version $129, http://www.fmjsoft.com/
Soundfaction Alive, $39, http://www.soundfaction.com/products.htm
These are the top players, I'm sure there are others as well
