Get a Dell dual-core desktop for $299
Though a graphics lightweight, the Dell Inspiron 530s comes with enough horsepower to handle mainstream computing chores.
Check it out, baby, check it out (sorry, been watching too much American Idol): Dell's rocking Inspiron 530s desktops for just $299 (plus 30 bucks or so for shipping, and possibly sales tax as well).
The configuration includes a 2GHz Pentium E2180 dual-core processor, 1GB of RAM, a 320GB hard drive, and a DVD burner--all wrapped in Dell's sexy little slimline case.
Like games? Keep looking: The integrated Intel GMA 3100 graphics are more suited to Peggle than Portal. It's just as well, then, that Dell bundles Vista Home Basic, which lacks Aero, Media Center, and other graphics-intensive features.
Indeed, this is a system for grade-level students, home-office users, and others with fairly basic computing needs. That said, it's a nicely equipped desktop for the price, and it includes a one-year warranty and 24/7 phone support.