@axxo: If video encoding is what you want to do then you should be mainly looking at clock speeds. RAM, Graphics Card, motherboard, Dual Channel RAMs, etc have very litte relevance here. So if you really want to do an aXXo style rip-o-mania, I suggest you go with 1GB RAM @ 667 MHz, that XFX 630i mobo, or even a cheaper board, and Core2Quad 6600 Processor. A light overclock on the processor will be enough for high encoding rates. As we speak, the x264 encoder is undergoing major revisions to speed it up while maintaining its quality, as well as to better support multi cores.
So in a nutshell: for video encoding, just go hyper on the processor.
But if you need a more balenced system, I suggest you try the AMD X2 processors with Brisbane cores, which can be overclocked easily. The motherboard for that prcessor will also be quite cheap.
Go for a 4k brisbane processor(forgot name sry), 1 GB 667/800 MHz ram, one of those good 2.5K boards I and cheeta were discussing earlier(again forgot name, sry) and a basic card(or even onboard.) It will come under 7k to 8k for you.