Alrighty, you guys may remember me from my thread about my poor processor performance in the games section

I wanted to give a belated howdie.
That out of the way, Im going to upgrade my dell dimension 4700 by basically throwing the case,
mobo , and the old processor out. Ive already selected my motherboard , which is this.
Asus M2R32-MVP ATI CrossFire Xpress 3200 Socket AM2 2000MHz DDR2 Motherboard at ZipZoomfly
Asus M2R32-MVP 580X CrossFire Sempron/Athlon 64(FX)(X2) SktAM2 DDR2 ATX Motherboard w/Audio, Gigabit LAN, RAID/Serial ATA
This will cost me about....160 dollars. Is this a good pick?
Now my dilemma is selecting a good gaming amd processor. I obviously dont have 500 bucks to blow on one.... my total overall budget is 300 bucks... could push it up to 320-340 if I had to for the processor. So lets put it at 340-160 = 180 bucks for the processor. I have NWN 2 , Oblivion , Counterstrike : source , guild wars , and am planning on getting WoW , Battlefield 2142 , and probably the latest dx10 game in the future. An upgrade to vista is planned later on , along with a crossfire configuration. Ill be recycling my hard drive,
ram , etc, which is listed above in my comp specs bar.
The processor I have picked out is this.
AMD Athlon 64 X2 Dual-Core Processor 4200+ Socket AM2 Retail at ZipZoomfly
AMD Athlon 64 X2 Dual-Core Processor 4200+ Socket AM2 (89W)
This costs....170 bucks.
I did some research and I found that X2 processors failed the clock tests for FX , kind of like a 1900 XTX getting scaled to a GTO for failing the clock tests. Is this better than my p4 , and will it give me the smooth performance I want in css , oblivion , etc?
If not, what would you reccomend? If it does , but you have a better choice, please post here. My budget is very limited at this time , but Im planning on ordering this thursday (feb 1st).
All help is very much appreciated
