Those specs of yours are average. Regardless, if you're to have the best system, you still won't be able to run it since the emulator will be the bottleneck.

By extreme, I didn't mean THAT extreme, just a good system like high OC P4 or Dual core AMD & Intel series OCed, X1800XL or 7800GT, 2gb DDR2, etc. That sort of thing. if you want to go for extreme, then Athlon FX series or Intel EE, X1800XT Xfire or 7800GTX SLI.