For the budget you've got there, you really can't do any better. It's not overclockable, but as your first build that's not a bad thing. And even without OCing, the 3350P is formidable for gaming and productivity. I prefer the 7870 over the 660 because of the limited memory controller, but for casual to mid-range gaming it isn't a problem.
Just be aware that Microcenter ( your mboard is currently selected from there, ) doesn't ship, so you have to pick up orders there in person.