i know it sounds obvious,but just google 'free drum kits wavs' or something like that.yall find a few kits that way.or just search for other forums(even this one)because alot of members post up their personal kits for download.
if you dont mind spending a bit of money,try gettin some vst plug ins,i use native instruments FM7 for old school synths,Absynth 3 for weird synth an percussion loops,edirol orchestral for orchestral obviously!
also try native instruments Kontakt,as that is a dope sampler but has shed loads of instruments samples,like 4 gigs worth,an also lets u edit ya own samples from vinyl or wherever,an make them proper instruments that you can play on your keyboard like a plug in.
reason has some dope instruments,but i find that if your used to FL it seems a bit weird using the sequencer.probly just me tho!
i use reason purly as an instrument that you sequence in Fruity thru rewire.
probly no help what so ever,but i tryed! peace