maybe an old i5. the new i3-3220 will smoke it especially in single threaded programs/games. if you are getting 7870 is march buy the i3-3225 and use the HD 4000 graphics until you get a 7870. there is nothing wrong with the corsair CX430 V2.
One of the main reasons i went with the FM2 is because AMD will still support it for quite a while and the next gen APU or possible FX's that might come out for it will smoke the I3 3220. I will never be able to spend 300 bucks on a i5 or i7 untill i am 15 and can get a job. Which won't be for a little over a year from now.
Look i am very tempted to get a i3 3220 but the a10 build just seems to be better.
But if the A10 were to bottleneck the 7870 then a guess i would have to for the I3 instead.
you dont want a apu if your getting a graphics card. the whole point of a apu is so you can build a cheap computer without a graphics card. i wouldn't hold your breath waiting for a FM2 cpu that beats an i3. plus i thought they were coming out with a FM2+.