I suppose in 2-3 years DDR2 ram may become very valuable in resale when it will be scarce.
I doubt DDR2 will be as valuable as DDR1 is right now. DDR2 -> DDR3 was a softer transition, DDR2 has been been a standard for too long and has seen lots of low prices in 2GB and 4GB sticks in its lifetime. DDR1 -> DDR2 was a harder transition, DDR1 was never really cheap, and never sold a lot of sticks in 1-2GB volumes, which is why they hold their value well (IMO, of course).
OP,
It's also not a bad idea to wait and see what AMD's 6xxx series brings (as someone else suggested). Should be seeing benchmarks by the end of the week, if not tomorrow. But upgrade video card first, then probably Q6600. Again, as it's been stated next gen Intel is due out in a couple months, so it's hard to justify upgrading an entire new system right now, but I also hate recommending investing in s775. But you're really hoping a new GPU will make everything up to par, so you can stave off a partial or full upgrade for a little while yet.
