May I suggest that for the usage you describe, you are overdoing it quite a lot there. I would recommend one of the £50-£60 duel cores, such as the Intel E5300 or the Athlon II X2 250.
I'd recommend the following motherboards, well you could use any 785G board that OcUK sell for the AMD really, but
this one is one of the cheaper ones and apparently it's also very good, has integrated graphics with hdmi too, you should be able to do hybrid crossfire with your 4770 and the boards HD 4200, which is a bonus.
This board should do the trick for the Intel, and will work out a little cheaper than the AMD setup in this case.
Being as you don't actually need integrated graphics it does give you quite a lot of options, I chose the AMD board with, because it's actually slightly cheaper than the 770 based boards that don't have integrated graphics, and there is no benefit to the 770 chipset over the 785G as far as I am aware.
My own personal view is that you should go with the AMD setup, it's a newer platform with an upgrade path for the future, and the 785G is a cracking good chipset and the new Athlon II's are cracking good cpu's, they clock very well and don't use an awful lot of power doing it, plenty of punch for what you describe too.