Quad-core desktops have been mighty popular of late. The ones I've posted in recent weeks have all sold out in a matter of hours. I think that's because a lot of folks are looking to replace their aging Windows XP boxes with something more powerful--and Windows 7-powered.
J&R has a refurbished HP Pavilion p6247c quad-core desktop for $369 shipped. I won't say this is the best configuration I've ever seen, but it packs more than enough punch for most home users.
The system's heavy hitters include a 2.6GHz AMD Athlon II X4 620 processor, 6GB of RAM, and a 500GB hard drive.
You also get the obligatory LightScribe DVD burner, media-card reader, and a half dozen USB ports. The OS: Windows 7 Home Premium 64-bit.
As for graphics, the Pavilion relies on an integrated Nvidia GeForce 9100 subsystem; it's good enough for everyday operations and even some older games, but definitely on the weak side for anything requiring a lot of video horsepower.
Fortunately, there's an available PCI Express slot, so you can always upgrade the graphics later if you want.
As with most refurbished desktops, this one has a 90-day warranty. Given that this system cost $800 when PC Magazine reviewed it back in October (though that was with a monitor), I have no problem with that.
Indeed, $369 for such a rocket-powered system is hard to beat, which is why this will absolutely positively sell out fast. Hopefully it'll last long enough for you to get one if you're interested.
Bonus deal: Today only, Woot has a refurbished NeatReceipts sheetfed scanner for $69.99 (plus $5 shipping). The bundled software turns it into a complete receipt/document/business-card management system. I've got one of these things; it's awesome. And it sells for $200 new.