Currently the best priced desktop with a Quad Core processor. Amazon, Fry's, Circuit City and many other retailers sell this PC for $800-$1000. It uses an ASUS IPIBL-LA motherboard. Comes with 3GB of RAM (2 1GB and 2 512MB. 32 bit OS like Windows XP and Vista don't recognize RAM beyond 3 GB so this is optimal unless you "upgrade" to a 64 bit version of Windows, and if you do that, all I can say is good luck finding device drivers!)
I got one awhile back, and while the LightScribe/Roxio software won't burn a LightScribe label, everything else works fine and it's good PC. I did stick an EVGA DX10 compatible PCI-E board and a wireless-n board in it as well.
It also has an HP Pocket Media Drive bay, but as I already carry around a pocket USB drive, I haven't used that feature yet. No need to buy another drive at this time point anyway.