OT: I've had an e-machines desktop for the past two years and have no complaints....and got a lot more for my money than I would have gotten from one of the bigger names.
Tiger Direct ussually has some good deals on e-machines and other computers too: http://www.tigerdirect.com/
Edit: Actually the e-machines on the top of the Tiger Direct webpage looks like a pretty good deal.
I have 3 eMachines desktops at home. They work fine. I have run into no problems at all with them. Had a lot more hassle with the various HPs and COMPAQs I have had in the past...
Low-end desktop PCs are commodities--there is no reason to pay up for a brand sticker on the case.
Should be able to get one, with XP on it, and an eMachines monitor and Lexmark printer thrown in for about $350 after rebates at Best Buy. Sometimes they will discount further if you can take a display or "open box" item.