i7 = i5 when it comes to gaming. Very few games utilise hyperthreading, and you don't get a major performance boost, very minimum. Considering games are mostly GPU now, it won't really affect it at all.
If you are gaming at all, or even light editing, it is not worth to pay the extra $100 on a n overclockable i7 CPU, with an unoverclockable board.
Seasonic = Corsair. Seasonic makes Corsairs Power supplies, and Corsair sell the same thing for much less than Seasonic. Corsair also typically include more warranty, and black cables, which usually match the motherboard much better than coloured cables.
I recommend this PSU if you can fit it into your budget, hopefully your savings from the i7 can cover it, if not, the CM PSU should do fine. Its not that it is bad, its just not as reliable as it can be. Otherwise, you can use your i7 savings to get a MUCH better board and quite a bit better GPU.
I really hope you would change out the motherboard for the one suggested, you have an overclockable CPU with an unoverclockable board, not to mention they are nearly the same price and the Z77 IS MUCH BETTER, being able to support two way SLI/Xfire.