This is quite a big leap your making. As much as I like to promote Linux
based pro-audio, you should make very sure that changing out your entire
system like that won't cause you problems.
I am gearing towards an RME Hammerfall card
and a behringer A8000 adat interface.
I would rather recommend buying the Alesis AI-3 if you want to use the
ADAT interface. This gives you more freedom to use various preamps.
(IMO, berhringer's preamps suck) If you've got money you may want to
invest in a nice preamp.
http://www.soundpure.com/browseProductType.do?id=5
-Reuben