Gaming/cad $1000 budget

Approximate Purchase Date: this first week of november

Budget Range: $1000 or below

System Usage from Most to Least Important: gaming, CAD(not 3d),rendering,video converting.

Parts Not Required: nothing, starting from scratch here

Preferred Website(s) for Parts: newegg

Country of Origin: US

Parts Preferences: im not picky

Overclocking: try?

SLI or Crossfire: Yes

Monitor Resolution: dont know, i just want it to be HD

Additional Comments: i want a silent and strong pc that would last for at least 3 years? but with the budget. and a GTX 470 has caught my eye. maybe i would also want that. or that gtx 580? or ati 6900's series.