Need Advice on Partial Upgrade

Hello folks,

This is my first post on TH, so I'd like to start with a "don't eat me please!" and also "Hello all!". I'm currently saving up for a decent system which will primarily be used for gaming. In this post I'd like to get your feedback on my selection so far, and to try to get you to shout at me something along the lines of: "What did you do that for you idiot!?"

What I want
So without further babbling the parts I've selected so far are as follows (For these parts I'm on a total budget of around 600 euros):

Processor: AMD Phenom II X4 955 / 3.2 GHz - Black Edition - L3 6 MB
CPU Cooler: ASUS Silent Knight II
Motherboard: Gigabyte GA-MA790FXT-UD5P - ATX - AMD 790FX - Socket AM3
Memory: OCZ Platinum - 4 GB ( 2 x 2 GB ) - DIMM 240-pins - DDR3 - 1333 MHz / PC3-10666
Hard Drive: Seagate Barracuda 7200.12 - 1 TB - 3.5" - SATA-300 - 7200 tpm -buffer: 32 MB

What I have at home
The rest of the parts I have at home from my previous system. I have a 550w PSU and a XFX GeForce 8800 GTX 612(?)mb RAM which will be transferred to this system and upgraded a little later on, I also have a Coolermaster Ammo 533 case.

With this system I plan on overclocking the processor a bit, as much my case/cooler will handle. In addition to that I will not being going for SLI. Furthermore I have two monitors which run at 1680x1050.

Where I'm heading
My goal for this PC is to make a powerfull multi-purpose system which leans towards gaming performance. I do not care too much about noise. Flashyness would be a nice addition but not a primary focus.

So once again, my question to you all is, if you have any suggestions or obvious improvements that would be greatly appreciated. Also, suggestions for the future upgrades of Case (mid-tower), PSU and vid-card (nVidia preferred) would definetly be appreciated.

Thanks in advance for all of your responses,
- Nom4d

With my supplier I won't be able to buy a combination of those for less than around 390 euro. Which means with all the other parts around the same price I'll be spending quite a bit more than I will now. Is the performance increase really worth it to go to Intel i7-920?