I've decided to up my budget a bit. It'll mean I have to wait a bit longer a work a bit more, but I think it'll be worth it:
Gonna switch the 8600GT with this 9600GT:
Newegg.com - EVGA 512-P3-N861-AR GeForce 9600 GT 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Supported Video Card - Desktop Graphics / Video Cards
Don't want to risk anything by having a weak and/or crappy psu, so I'll add this:
Newegg.com - CORSAIR CMPSU-550VX 550W ATX12V V2.2 Power Supply 90 - 264 V UL, CUL, CE, CB, FCC Class B, TUV, CCC, C-tick - Power Supplies
The cost now comes to about $660 now (Before taxes, shipping, and mail in rebates).
What do you think?