System's Check

[lazyr03]

I plan on building another desktop mainly for faster video encoding and multimedia related things. I would like some opinions on the parts I'm considering.

CPU: AMD Opteron 165 Denmark
Mobo: MSI K8NGM2-FID Socket 939 mATX
Ram: G.SKILL 2GB (2 x 1GB) DDR 400 Dual Channel
Main HD: WD Raptor 74GB
Storage HD: Probably Seagate Sata HD 250-400GB
Video Card: Probably Nvidia Geforce 7600GT PCI-E
Case: Cooler Master mATX Case
PSU: Xclio 450W PSU
Cooling Fans:
Thermaltake A2018 120mm
ARCTIC COOLING Pro TC 80mm
Optical Drives and other stuff I have.

I did some research on the CPU and it's possible to overclock from 1.8 GHz to 2.4+ Ghz, so I plan on overclocking. I am set on the CPU but any comments on a change of anything else is welcomed, such as if I need a different/better PSU. This motherboard is limited to about 2.2 GHz overclock for this CPU, but I still find that is resonable. I'm mainly concerned with the amount of heat that will be generated. I prefer a mATX setup but I would consider a regular ATX setup if the mATX setup is too small to allow enough airflow, such as with the overclocking and raptop harddrive. If air flow is not good enough in this mATX case, what other non-SLI 939 ATX boards is recommended that still provides enough overclocking options?