E6600 motherboard + ram

Sorry...not up on the conversion rate.
Since you're limited as far as budget, I guess crossfire and SLI are out of the picture. That leaves you with one REAL choice....a P965 chipset. I have to give the MSI version the thumbs down because I've seen guys having trouble overclocking successfully and the mobo presently has no capability of lowering the CPU multiplier.
I've got 2 512 sticks of memory, and the sweet part is if I decide to add 2 gig sticks, there's no incompatibility issues. This chipset will take mixed sizes. As you can see, with proper cooling, my motherboard is perfectly capable of rather high OC's. the only thing really holding me back right now is my memory. It's already overclocked to DDR2-900. I'd like to get to 500+fsb setting some day, as I've seen it done. I'm already @ 506mhz northbridge FSB, but I know there's more to be had.