Yo,
Get some of those free vst's of the net. heres a sick ass page with a whole slew of VST instument and effect links. The vst's I mainly use in my hip hop production are Good orchestral strings, a minimoog synth, a harp, a nice piano, and a guitar simulator vst.
heres the link to some of these free vst's. Lots of synths for techno, but some work real well for hip hop.
www.futureproducers.com/forums/showthread/threadid/94385
for bass and all different kinds of crazy instuments like bells, xylophones, flutes, hand drums ect.. I use soundfonts. You will need a soundfont player vst to play them however.
heres an extensive site with alot of crucial soundfonts. Peep the naturally decaying bass in the bass section.
www.hammersound.net/
hope this works for ya. If you have any questions about how to load in vst's or soundfonts holla at me.
Peace,
Cincinnatti, OH.