I came by a i7 2700k for free and I have $550 to blow (very strict). This system will be used for gaming ONLY. I would like to upgrade the system in the future by adding another graphics card so I need it to be sli/crossfire capable. Please give me your suggestions. Here are my current considerations for the power supply, motherboard, and gpu only.
$529 (After rebates) Plus shipping. Well within your hard cap. Get a $230 GeForce GTX 560 Ti if you can spend $90 extra, but at anything less than 1080p, that will be a tad much for now, but with games becoming more GPU dependent, a couple of years from now, you'll still be able to at least get by on that as opposed to the 6870 maybe.
I won't spend the extra on a bigger PSU to xfire current gen GPU's because of THIS.