Both will work but really there is no point in getting the APU if you are going to be getting a discrete graphics card. The integrated graphics is the best feature of the APU and hyou won't be putting it to use.
Sorry, I meant just an Intel CPU with a discrete card, not a card in addition to an AMD APU.
Exactly which video card are you thinking of getting?
I guess a 6670 or its Nvidia equivalent, as I'm not really a gamer. I've done a little bit of research but still don't really know what to look for. The GPU hierarchy is helpful, but all the specs of the various cards themselves make my head spin.