The i5 2500k is way more than enough when it comes to gaming. The only thing that i7 2600k adds is hyperthreading which is mainly important for CAD and other non-gaming related programs. If you really want to game the i5 2500k is perfect. Also, the "k" means it's unlocked for overclocking. So if you are sure you will never overclock, then you can save ~$30 by getting the 15 2500.
The only other thing is is the motherboard. The sabertooth is an extremely nice motherboard, you really don't need THAT good of a motherboard. Here are my two recomendations:
Yeah, I've got the i5 2500k and the ASUS P8P67 board and it's FAST!! I downloaded the Crysis SP demo and smoked my way through it. Video clips literally launch in a split second!
I would say if you go with arctic silver, put a very thin strip from top to bottom on the cpu WITHOUT touching the ends and that's it. Arctic Silver has info on how to do this on their site. My CPU stays idle at 32-33 C and gets up to 52c in Crysis. Prime95 brought me up to 67-68 C which isn't too bad.
Get the ASUS P8P67 and the i5 2500k and you'll have a nice system! Make sure to install Windows 7 64-bit though!
And you could get a ANTEC 500 watt PSU and be fine I believe and the "Illusion" case is nice!
You could cut costs on the processor with the i5 as stated, but also the case you could get the 300 illusion for 30-40 bucks cheaper than the 900 (you lose the side window, but otherwise looks the same) and get a smaller power supply unless you are going to sli in the future. I personally prefer the Radeons, but that is not a bad card..
I agree with EPBaseballer14. Cut the CPU back. An i5-2400 (or 2400S) would be fine too.
For only $1 more (because shipping is free), get the 650W Truepower New. It is semi-modular which will make cable management a little easier, and it is more efficient: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Also, do not go cheap on the PSU! It might not be the fanciest or most exciting part of the build but it powers everything. Brands that I have had luck with include antec, corsair, and my personal favorite XFX. I'm usin the 750w XFX black edition in my build right now and it's working like a charm.