Ditto to Joe. I have a few Dells here and many at work. Best buy for the money IMO. You can check the Yahoo's home page and Slickdeals.net for great deals. Yahoo usually has one deal ona week.
To add, I'd go with a 60-80 gig HD to start then buy a 320-400 gig unit on sale afterwards. They are very inexpensive ad it'll take little effort to add on. That should cover you for a bit.
This from Yahoo/shopping/computers (featured on MSN as well):
http://www1.us.dell.com/content/topics/segtopic.aspx/odg_special49?c=us&cs=19&l=en&s=dhs
300 Gig Seagate (SATA) for $110:
http://www.slickdeals.net/#p6952