Building a new system - Bit of help

Hello,

I will be building a pc soon.

CPU: AMD Phenom II X4 850 (3.3ghz - no oc - everything retail stock)
Motherboard: Asrock N68C-S UCC Motherboard
RAM: 8GB Corsair DDR3 1333MHZ RAM
Optical Drive: LiteOn DVD±RW/DL 22x
HDD: 1TB Western Digital Caviar Green
Graphics: VTX3D 2GB Radeon HD 5450
PSU: Corsair 500w (CX500V2)

Case: Novatech Prowler Midi Case V2

Other accessories -
VIA Sata PCI Card
3.5" all in one memory card reader


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As a note this is by no means a gaming build.
I might upgrade the graphics card to a HD5670 if I need a more demanding graphics card, although I doubt it. I have taken my time but can you see any flaws in my combination?

In regards to airflow and cooling.
The case comes with 2x 120mm case fans and I've decided to buy 1 more 120mm fan (Xigmatek XLF-F1256). There is no details available for the cfm for the 2 case fans that come with it, the xigmatek has 61cfm. In my opinion 3x 120mm case fans should be adequate.
It will be set out as follows.
1x 120mm case fan at front (intake)
1x 120mm case fan at back (exhaust)
1x 120mm case fan at top towards the back (exhaust) - Xigmatek
-Plenty of vents
-Atleast some cable management
The case has plenty of space for more fans, but I rather not use them if not needed since more fans = more money, more power consumption and more noise. (although I'm not too bothered about noise)
Do you think this would be adequate? Any flaws?

Now regarding the PSU.
This case has one of those new designs where the psu is put at the bottom of the case.
It has a hole at the bottom with a filter.
The pc will be sitting on the carpet at all times, so I thought it might not be a wise idea to keep the fan facing the floor. Would it be better if I faced the psu fan upwards instead.

Your help is appreciated.