oh and forgot to mention, here you can check if your firewire
cards work in Linux, MOTU for example:
Device support database | ffado.org
If your planning to go the Linux route go RME, altough they don't make opensource drivers, they provide the hardware details to the lads of ALSA to make the perfect drivers (For people who know the same as Nvidia vs ATI discussion). And the peops from alsa made the software mixer to go with. While the likes of MOTU do nothing, they don't make drivers or hand out details. So the people of ALSA have to reverse engineer those drivers to be able to make them. And they do this in their spare time, and they live of donations! Of course nothing would be possible without the help of the community, ALSA is no company but a community. As is the Linux community who financial, and in other ways support those and other projects. Ardour isn't making their money buy selling their products, but live purely from donations, mostly from the community, and certain companies like Harrison, and used to be financially supported by SAE and SSL. And as far as I know the Ardour dev team isn't loaded like the people from Avid :P.
So remember when you get into Linux, you also get yourself into a community and the ubuntu forums are a great place to get all questions answered.
cheers,
p.s. My setup:
Ubuntu Studio 9.04 (have to upgrade it to 9.10)
RME Hamerfall 9652
Yamaha 01V96 (adat)
etc. etc.