[linux-audio-user] Digital mixer advice

Hi all, I've been lurking this list for years... just finished school... got a job... and got the ccrma disks and just went crazy for a while. SO I'm succesfully multi-tracking in Ardour - using/syncing with hydrogen and editing wav files with audacity. First off this software is a total blast! My hardware is a 2.26GHz PIV and an ASSUS MOBO, SBLIVEEMU101K, 512MB RAM and old cheap everything else. I find I can have disk XRUN problems with four tracks of audio and 48ksampling... knocking down the sampling rate helps... using any video card related function... like moving the mixing panel... doesn't help :) I've got lots of guitars... amps... basses bongos etc. and an old roland synth. Couple of questions... editing audio from Ardour... what is the most well used solution? Will using flux box instead of GNOME see me an improvement in my audio performance. I used to use this product from propeller heads... I forget what it was called but you could put a sampled drum loop in, and it would extract info like bpm, and line it up for you etc. any equivalents in OS? Lastly I am looking at getting either a digital mixer with say 8-16 ins and a digital in card to interface with linux... or getting a faster system and AD/DA/midi/digital in/out card. Could some you you with either setup let me know the brand names/models you are working with and how its going for you...so I can go do some research? There are so many options I just don't know where to begin. I'd like to see stuff that is really well supported by ALSA/ardour. Is there a generally accepted best way to do this say at Stanford U or elsewhere? Again thanks all