Is there a USB sound card that works well with Linux?
I am trying to upgrade the sound in my laptop to take advantage of the new speakers that I bought

I am looking for a card that does USB and 5.1 (at least) channel output
Nothing else matters (Digital, Remote)

I have seen:
Creative Extigy (Can't find one to buy)
Creative Audigy 2 NX (Don't know if it works)

Does anyone have any expirance with these, or know where I can purchase an Extigy