The 4400+ (2.2GHz and 2x1MB cache) is only 2.2 frames faster then the 4200+ (2.2GHz and 2x512kb cache). This goes to show that cache doesn't help that much as people make it out to be. But don't get the 4200+, get a 3800+ (which is only 1.8 frames slower in oblivion, but is 60 bucks cheaper).
I would get most of the HW from newegg.com :
AMD X2 3800+ $297
G.SKILL 2GB DDR400 RAM $152
HIS X1900 XT IceQ 3 $480 w/ 30 dollar rebate = $450
Antec TP2.0 550W $90
WD 250GB 7200 $90
DFI Lanparty Ultra-D $123
X-FI XtremeMusic $117 w/ 30 dollar rebate = $87
Thats $1349 before shipping and rebates'
This gives you money to spend on the case and DVD-RW, as well as Windows XP if you don't have it. Raptor HDDs don't have good price/performance ratio so I recommend against it.