The SB Live can only RECORD a stereo signal at one time, but as far as playback, that will be dependent on your system, primarily the hard drive.....the software you pick may also limit the number of tracks you can use within it.....
are you building from scratch?...if so, you may wanna post a budget in $$$ and breifly descibe what you want to accomplish.....as the resident cheapskate, i can show you where to cut $$$ corners without taking away too much quality....the old saying "getting 90% of the quality for 50% of the price"...one of the knuckleheads here said it now its in my mind......
some of the guys here no so much about putting together computers that its sick.....
Good Luck,
Aly's Dad