Check this link out for a deal thats going on for dell
Dell Vostro 200 Desktop: Core 2 Duo E6550 2.33 Ghz, 1GB DDR2, 80GB HDD, DVD-ROM, 20" E207WFP LCD, XP Home Or Vista Home Basic $519 - SlickDeals.net Forums
But thats up to you if you want to get a pre built pc.
It all depends if your going to oc or not.
And do not get the 8500gt if you plan to game, its not worth the money.
You would be better off getting a 7600gt.
I am hating dell at the moment since they delayed one of my shipments untill the 16th of september so I just cancelled it. IT was a big hassle though.
I just got the e6550, and a good mobo, so im excited to get it and find out its potential.