"Specifically look up ISP1160 which is USB host peripheral chip."

Oh yes, so it is!

http://www.semiconductors.philips.com/pip/ISP1160BM.html

But look at the processors they're recommending to drive it:
* Hitachi ® SuperHtm SH-3 and SH-4
* MIPS-based (tm) RISC
* ARM7 (tm), ARM9 (tm), StrongARM ®

certainly doesn't sound like a job for an 8051 - see Michael's post above