Regarding RT and ardour, you can run jack and ardour without RT.
Good point. Although I'm not using the -rt kernel anymore, my ubuntu jaunty (and
intrepid before it) system works very well for audio stuff. I easily run ardour
and jack and others and they are very stable. I found that I did not need the
super low latencies (<5ms) from a -rt kernel to do the recording and playback
that I was doing.
Last time I had a really good -rt kernel was around Gutsy. I did a lot of
tweaking for that also, but it did work very well with the workstation.
Also FWIW I was never impressed with WindowsXP's latency - Stopped using that
about 2.5 years ago and never could get the latency down low enough for live
playing using a software synth. So one should not just assume that Windows will
give you the super low latencies of a -rt kernel.
The best low latency I've ever gotten from my current desktop was using the
64Studio distro a few years ago. But I've never tried the Fedora, Suse,
Mandriva versions so can't comment on these.
Hope this helps someone.
Geoff