dude if ur getting the parts now then u definitely want an AMD dual core, its not all about numbers, an amd x2 3800+ might have 2.0GHz, but the 3800+ means its just as effective as an intel thats clocked at 3.8GHz, but thats only for gaming, which is ur purpose, everything else AMD still wins, haha. ram changed to G.skill or OCZ or Crucial or Corsair, and i for UT2007 u will definitely need 2 GB duall channel, just get a value version, they are about $150. as for card, for a UT2007 u want at least a 7900GT, or an ATI X1800. and for board, just get a MSI K8N neo4-f seeing as how ur on a tight budget, i think.
EDIT: but if ur buying this summer, then u definitel want an Intel Conroe, or its other name, the Core 2 Duo, or something like that.