Not a bad system by any means. However, there are some issues.
The i3-2120 is multiplier locked, therefore can be paired at full potential with the Asrock-H61m-dgs and cheaper ddr3-1333 ram.
The 550 ti is terrible in comparison to the 7770. The 6850/6870 are logical alternatives to the gtx 560.
The stock intel HSF is more than enough to cool the 2120 as intel issues the exact same cooler for the 2500k.
A pure value-based build would spend only $50 on the case and psu and get a rosewill combo. The options you picked are quality steps up, it's just that I'd pair them with a more powerful system.
Im not going to overclock this yet since it's my new build that's why i choose i3 2120 over i5 or i7.
For the stock..hmm im not going to use it since my country had a temp issues and the place where am i is not air conditioned. I choose it over the stock because i will use it for the near processor upgrade.
Anyway.. Did my GPU overkill my gaming on 1600x900 resolution? I only use 20'' inch monitor.
If the build is centered around "upgradability," then you should have bought an even larger power supply in case you decide to trick out your graphics cards.
It is highly unlikely that even in extreme conditions the stock HSF would be a problem, people have run the 2500k overclocked to past 4 ghz on that beast, using more than twice the power you will.
And yes, the hwcompare site is a joke. Real world benchmarks kill the 550 ti.