....no, it really doesn't matter what the timings are set at in this case. The performance gain from 2 to 4 gigs of memory (in a 64bit OS environment) would make the timings somewhat insignificant. You have to realize that the performance gain going from 800 to 1066 is barely noticeable.
At this moment, the DDR2 800 kit I'm about to post is the same cost as the 1066 equivalent. Watch the price on the 800's, they fluctuate a lot.
Well, you'll top out around 3.5gb total memory, which means you will only be able to use 2.5gb of your RAM approximately with around a 1gb video card. Like I said, getting a 64-bit OS would be really useful.
It would be, but that would require a lot of extra work in terms of migration. At the moment I'm just wondering what would be more beneficial in a 32-bit environment.