usb soundcard for linux

[andy baxter]

Can anyone recommend a decent quality usb sound card for linux?

All I actually need is something that will record and playback at good 
quality (ideally better than CD but not important if not), and has a 
midi input and output port.

Beyond that, it would be nice if it had more than one input, proper 
professional mic inputs etc. I'm looking more for something that's for 
home recording of music etc, rather than 5.1 surround for home cinema 
playback or whatever.

I've been looking through the soundcard matrix at alsa-project.org, and 
haven't found anything that looks suitable so far.

thanks for any help with this,

andy.