have look at the AKAI EIE PRO, biggest bang for the buck imo.
and a low latency you normally only get for 3 or 4 times the money (RME stuff fe)
soundwise it's close to that mid-range stuff and you'll need headphones to really tell the difference.
a Focusrite around 200 I heard has lot of latency I'm afraid.
(forget about the red AKAI EIE tha's a little cheaper, it's only 16 bit...you need the silver Akai box.)