I started this build last year but I couldn't finish it because i didn't have enough cash or time to continue it. This is my first ever gaming build. Currently i've spent t around $260. So my budget is going to be roughly $800 not including monitor or keyboard or mouse. So here goes.
Budget Range: $800
System Usage from Most to Least Important: gaming, video editing
Parts Not Required: Already have mobo, psu, keyboard, mouse, monitor.
If you want to save some money, then the core i5 760 is a much better value than the 870. You'll save $100 which you can definitely invest in something else.
Your mobo supports both SLI and XFire so as long as you get two of the same, your mobo will be able to utilize both. Although personally, I'd rather get one high-end card than two mid-end cards. Just less hassles to take care of.
If you have $800 after the mobo and power supply, I'd recommend buying a more expensive graphics card, like an Nvidia 560 Ti or an ATI Radeon 6870.
Here's a good chart for comparing graphics cards. Just remember to buy the same brand if you're going SLI or XFire. http://www.tomshardware.com/reviews/best-gaming-graphic...
So is that $800 what you currently have or is it before deducting the price of the mobo and PSU?
You should really get the i7 760. You lose $100 for .13 Ghz extra, which is a terrible deal.
You will probably find a great deal for the i7 760 because newegg and other companies probably want to stock the second generation of sandy bridges.