look at korg, I have an ax10g, but apparently they now have like an ax1000g, and like an ax2500g or something like that.. really inexpensive. I'm assuming that the higher models would be alot better then mine, and mine wasn't all that bad.

if you want the best though, it's pretty much down to the GT-8 and the GNX4, but you'll pay a pretty penny for them