Been using Audition 3 on my laptop, with the Behringer UCA200 USB/RCA interface that came with my Behringer mixer.
It's a simple setup, but works very well for me - I'm able to take it along on gigs, and get pretty decent recordings, and I also use it for all my home recordings.
Could be that the real sound pros would wince at my quality and setup, but for my purposes, it seems to work well.
Been thinking about maybe trying a more official/professional software at some point though - I use Audition anyway for my media work, and it works very well for my purposes, but I'm curious to one day see what something like Pro Tools would do for me (I normally figure software out pretty quickly, so the learning part doesn't scare me).