XFX 850W Pro 850 PSU
Gigabyte Nvidia 560 Ti 448
Coolermaster 212 evo CPU cooler
Windows 7 64 home
Zalman z9 case
If you have spiked heat spreaders on that gskill they'll get in the way of the cooler master fan unless you only run one and put it on the other side. Not familliar with the zalman case fan placements would counter the exhaust fan on the back or running an extended atx board. OC'ing depends on 3 factors: the airflow, the ram, and how user friendly the bios is.
You're fine on the ram depending on how high you're wanting to OC. The more power you have to raise to the ram or vcore to get a stable OC post. More power more heat. Read the basic guide to OC it has links to freeware you'll need to monitor temps and run tests to see if you can maintain it under load. There is a good guide to the 2500k which is easy to OC.
Don't see the need for a SSD if you're not running raid, but everything else looks fine. Check your max voltage for your vcore and ram. Go over that and you'll over volt the Ram.
I've gotten mine up to 4.5 stable idle just to check temps before restoring back to defaults at 41 degrees idle.