If you got the time and some patience, you can go to One Laptop Per Child’s music library page and download around 10 GIGS of orchestral samples. You can get everything here; cellos, violins, flutes, clarinets, vocals, drumkits, sound effects, and just about anything else you can think of. The samples were recorded in wav format and includes samples from the Berklee College of Music’s sampling archive. Overall it’s a super cool download so what are you waiting for?
Go download 10 gigs of free samples from OLPC’s music library here.