M-Audio stuff is recommended.
I use a tascam US 428 (they also make US 224 and 122) USB audio interface that I'm quite happy with. Drivers are a-okay, and Panther update was out within about three weeks, so...
The Tascam stuff does 24 bits and sounds quite good.
If you're looking to invest in real quality, check out the Metric Halo ULN-2 two-channel Firewire interface. Has a pair of one of the best A/D converters on the market, includes two top-notch pre-amps, and sounds just amazing. Probably overkill for what you're doing, though.
-s*