My first build: Advice/Compatibility Please

Hi guys,
I'm a newbie building my first rig. The main purpose is mid-to-high end gaming (e.g. Starcraft 2, Diablo III, Skyrim, etc) with an interest to OC in future; final price ~ $1300. I'd appreciate any advice on the parts I chose (especially for the MOBO + PSU), as well for any compatibility issues I may have.

CPU: Intel Core i5-2500K Sandy Bridge 3.3GHz (http://www.newegg.com/Product/Prod [...] 6819115072)
- I went with this over the i7 because I read that the i7 is overkill on most games. Also, I have the option of OC'ing.

MOBO: ASUS P8Z68-V PRO LGA 1155 Intel Z68 (http://www.newegg.com/Product/Prod [...] 6813131730)
- This one is popular; decent reviews. Other than that I don't know too much about what I should get.

VGA: EVGA GeForce GTX 570 (http://www.newegg.com/Product/Prod [...] 6814130593)
- I went with the GTX 570 over the Radeon HD 6970 because it benchmarked slightly higher than for the games I like. If compatibility issues are a problem, I'd go with the 6970.
- I don't really know what the difference is with "Superclocked" version of this card is (aside from $20 more). Couldn't I just OC the normal card to match/exceed this?
- Though this is the GPU I will use, I may go with a different manufacturer brand (depending on HSF + warranty

PSU: SILVERSTONE ST75F-P 750W 80 PLUS SILVER Modular Power Supply (http://www.newegg.com/Product/Prod [...] 6817256059)
- I calculated my system's power to be 530-560 W. However, since I want to OC I picked a 750 W PSU (is this too much?).
- I'm not very clear on what compatibility issues I would potentially have compatibility

HDD: Western Digital Caviar Black WD1002FAEX 1TB 7200 RPM Hard Drive (http://www.newegg.com/Product/Prod [...] 6822136533)
- I didn't choose a SSD, because I don't think I need one.

Case: COOLER MASTER HAF 932 (http://www.newegg.com/Product/Prod [...] 6811119160)

RAM: I haven't really decided yet.

OK that should be everything. Will I need to buy an aftermarket heat-sink fan because I will OC? Or will the stock Intel one suffice? I appreciate all the help and feedback guys. This kind of thing can be really daunting for a beginner like me.

-Willy

Anybody?