Morning Paul.
Don't let a bad experience put you off external AI's*. I for instance run a Fast track pro into an old HP laptop, 850mHz, 512ram! That will run 2 tracks, 24bits 44.1kHz all day no sweat. That's about ALL it can do! No plugins, reverb or suchwhich but it shows that even a stupidly low pc spec' can be useful.
2.8G and 1G ram is a lightweight by todays standards I agree but you should be able to run quite a bit of kit with that if it is setup properly. Do go to
www.soundonsound.com and sign up to their forum and find the XPMusic optimizations. VERY important to do these.
Pci is the way to go and I would stick with M-Audio. They are generally recognised as having THE most solid and fastest drivers on the planet. Emu cards are excellent but I read their latency cannot get down to M's levels.
AP 2496 or AP192 if you want slightly better converters (but you will never tell, IMHO!) and balanced I/O.
*This is TOTALLY unsubstantiated but I have heard whispers of Lexicon drivers not being top hole before.
Rock on,
Dave.