I'm not aware of any exchange that has USD and more than 10 alts. That's my whole point.
I actually feel much better trading on a properly regulated platform like kraken or cryptsy. To me it means that the exchange can't just be wiped out or blocked by the government for failing to meet anti-money-laundering requirements.
I'm looking forward to some decentralized exchanges which obviously would be regulation free, but I'm not aware of any that are functional enough to use yet.