Glancaster :
Seems reasonable.
However though, what if I'd change both and take
Intel Core i5 2500K and Asrock Z68 PRO3-M S1155 motherboard?
That is a major upgrade of cpu capability. Do it if your budget allows.
4gb of ram is good if you will mostly be doing one thing at a time, like gaming. But if you tend to have lots of things open at the same time, 8gb is better.
Fortunately, ram is cheap these days. The current Intel nehalem and sandy bridge cpu's have an excellent integrated ram controller. It is able to keep the cpu fed with data from any speed ram. The difference in real application performance or FPS between the fastest and slowest ram is on the order of 1-3%.
Synthetic benchmark differences will be impressive, but are largely irrelevant in the real world.
Fancy heat spreaders are mostly marketing too.
Only if you are seeking record level overclocks should you consider faster ram or better latencies.
I would suggest the cheapest 8gb kit of 2 x 4gb up front.
Here is study on that:
http://blog.corsair.com/?p=65
The dual kit means that you get two sticks of ram. That is needed for dual channel ram operation. It is a minor performance item worth 1-3% as a guess.
Your case has usb2.0 in front. It is really only backup devices that can benefit from usb3.0 speeds .If you want to use usb3 speeds just plug the device into the rear panel port of the mobo. Otherwise the functionality is ok, any combination you use.
Your psu is ok, it is good for up to a GTX570.
With a 2500K, you are set for quite a while on the cpu front. I doubt that you will want an upgrade whenever the 22nm ivy bridge cpu's launch. The option will be there, since ivy bridge will be compatible with the P67 or Z68 chipsets.
If you should ever want more, it will be in the graphics area. The GTX560ti is a very good card at 1080P.
As a tip, download and read the motherboard and case manuals now. Many questions will be answered.