Welcome to the awsome world of hard disk... like going off the diving board and realizing there is no water in the pool...It is a long way to the bottom. No seriously, you'll love it once you get going. You are buying in at a good time for price /selection. 1st, go to prorec.com...all the info you could want.
2nd The safest most stable bet is go for a faster Celeron or P3 with as much RAM as you can handle...use Windows 98SE...very stable. Get something you can store to, I ate up a 14 GIG HD with 4 songs. You will however get a good track count(24 at least) and lots of processing room. You will most likely need an outboard preamp or small mixer, cause your sound card won't have the needed gain and it might be noisy.Ther's lots of cheap good stuff around new and used. More later, bedtime for kids