I would also recommend a Dell Inspiron 1100. And as someone else said just keep an eye on xpbargains for deals on this model. I'm typing on one right now. Actually we have two.
One is a Celeron 2.2Ghz, 256MB, 30GB, 15", DVD/CDRW $670
The other is a Celeron 2.0Ghz, 384MB, 20GB, 14.1", CDRW $640...