You probably wont need a 24bit 96K card at the moment, because even if you recorded at that, you would to convert it down to 44100 and 16bit for it to be on cd. the on thing that supports 24/96 is dvd.
Also, ive not had any compatibility problems
my delta 44. Ive used it for about 4 months now and it has been working great. ive used it on cakewalk, cubase, logic, vegas and all of them run just fine.
As far as your system goes. the cpu is fine as long you dont run realtime effects. the only problems you may have is with the harddrive. its best to record with 2 harddrives. one with your sytem files, and your faster and bigger one to record the audio files to. if you dont use two, you have a much more better chance of drop outs from the harddrive. your system hardrive doesnt need to be as fast as the recording harddrive. the recording hard drive i suggest a UDMA 66 7200RPM or higher and at least 10 gigs.
The reason for two harddrives, is if you have the system files on the same harddrive you are trying to record to, windows will need to look for certain files to run the programs, causing the hard drive head to move, which will cause a break in the audio stream.