ASRock extreme 3 $122 http://www.newegg.com/Product/Product.aspx?Item=N82E168...
The ASRock is a great board with many features. Get this board if you go with the i5 2500k because it allows for overclocking. This board also has 2 PCIe 3.0 slots for future xFiring which will give better performance
If you go with this set up, you won't be able to play next gen (2012) games on ultra (it's hard to play BF3 on ultra w/ HD 6870) but it will last a few years with decent High graphics performance @ 1920x1080...if your monitor is a lower res, then a little longer. If you go with the ASRock board, you can add another gfx card later to get a little more life from your PC by crossfiring the 6870