Sorry Brantyn but that is not exactly true. There are some games that are VERY CPU intensive, Starcraft 2 being one of them. It is the game I play the most and I can tell you that from experience. I think it also has some coding problems that add to the problem but in any case the CPU is much more important. The GTX 760 that I have can easily max it out and have no performance issues at all in 1v1 with my 4570 (non-K). However, in 3v3s and 4v4s, with maxed armies, I get terrible FPS drops during battles. By adjusting the CPU dependent settings I have been able to greatly alleviate the problem. So, OP, I can't speak about GSGO as I have not played it (just regular CS:S where I was getting over 120 fps with the laptop I had before building a desktop). However, about Starcraft 2:
If you want to play it with maxed settings and a lot of FPS you should invest more heavily in a CPU than in a GPU. The problem, however, is that the game does not utilize more than 2 cores all that well. 2 of the 4 cores of my 4570 remain under 50% even during the most intense 4v4 battles where I get FPS drops. The game simply does not know what to do with them. That is why if Starcraft 2 is important for you you might want to consider upgrading your motherboard and getting a 4670K which to then overclock. Definitely the more economic option (because you already have a compatible motherboard) is getting a 3570K and the performance will not be that different. By the way, what is your motherboard? If it is no good for overclocking I think the 3570K is not a good choice. If you don't overclock it there is no point in buying it. If you are going to overclock you are going to need a CPU cooler as well, something like the Noctua D14 if you are going with the 3570K.
Sorry for the rambling. In short:
If you intend to overclock AND your current motherboard is good for overclocking, the best option is a 3570K.
If you intend to overclock BUT your current motherboard is no good for overclocking, best go with a 4670K and a suitable motherboard, say an ASROCK Extreme 4 (or whatever is good value in your area).
In both cases you are going to need a good aftermarket CPU cooler.
Furthermore, if you only play 1v1 in Starcraft 2 the 3570K is more than enough. Hell, you could get away with a cheaper one even, like a 3340.
For a GPU, the GTX 760 is probably the best at the moment. It will be more than enough for both these games. I'd say even a 280x is enough but they are not cheaper enough in my area to warrant buying them instead.