Ubuntu Studio would probably be the best route. It has the low latency kernel enabled by default. It also has the audio programs you'd want installed by default. Don't know aything about the Focusrite Saffire, but I haven't been able to get any of my firewire audio devices working. So I'm using OSX for audio at the moment. Fortunately you can get some VST's working with ardour, but I haven't gotten that far yet. As ABF said, Seablade is the guy to ask.
7/22/07 at 1:15pm