Of course you will get all the usual suspects, but at least look at this one:
http://www.akaipro.com/product/eieproI took a chance on it, because I liked some of the special features it offers, and I couldn't be more pleased.
The original drivers truly sucked, and spawned a lot of bad reviews, but the current (2.9.55) drivers are rock solid.
I don't have any real amps here, so I am using amp sims exclusively. I also record a lot of soft synths played live.
In both scenarios, low latency performance is crucial, and it hasn't let me down.
Yes, it has an old school look to it, but those front panel controls offer a lot of flexibility.
It absolutely cannot be USB powered, and requires the included 3.5 amp power supply.
It's a sleeper, but for my money, it smokes other units in its price range($249)