If youre going to get an Intel gaming CPU then the i5-2500k is the best. Or if you don't want to overclock then i'd go for the i5-2400. Also, just in case it saves you some cash, i think you could get away with 500-550W PSU.
I have an AsRock board, 890FX, i would recommend the AsRock. The AMD setup is good, personally I would get the HD 6950 since that would be completely AMD, and if you wanted to later, you could do Crossfire.
I think the AMD one would be ok for games at the moment but you would probably notice the difference in going up to the Intel one, also it's going to last a lot longer. As for the AMD motherboards, i don't know a lot about them but i can vouch for ASRock as most of my boards have been ASRock, theyre great and i havent had many problems.