G.SKILL is the best for RAM IMO. 8GB is all you will need if you'll just be playing GMod and photoshopping and such. The 1866 is a good choice, but of course it'll cost more $/GB when you have a higher clock rate. Stick with at least two sticks because the 3770K (great choice, you will have no regrets) supports dual channel. G.SKILL also fares well with overclocking, especially with the higher clocks. I'd have to look into how much you can overclock it, but I'd assume the stuff I'm recommending can go up to 2000 MHz. Also lifetime warranty ye.

What I recommend for RAM: http://www.newegg.com/Product/Produc...D=3938566&SID=

I also recommend this aftermarket CPU cooler. On my i5-3570K I can get around 45 Celsius at 4.2 GHz maxing out BioShick Infinite. It is the best for the $30 price range: http://www.newegg.com/Product/Produc...D=3938566&SID=

Edit: Just a fair warning... Be positive your motherboard is compatible with the 1866 clock, because if it is not it could be read as 1333 or 1600, and thus you're not getting your money's worth. You can always return it, but it's a hassle if you don't put in research otherwise. If you happen to have any problems I've heard good things of G.SKILL's customer support.