Yes good luck with your PS.
I just upgraded my memory to 4 gigs from 2. I noted the comment previously that applications are limited to 2g so It might seem this was a waste. My thinking was that in game memory resources would be much less with everything loaded. This is because while the game is limited to 2 gigs, the operating system needs some memory too. This has turned out to be true. I now have about 1400Megs available for windows and the full 2 GByte for AH2.
I think with the price of ram being what it is (70 bucks with a 30 dollar rebate for Corsair DDR2 Dominator) for 4 gigs it doesn't make sense not to upgrade. I think you pick up some additional headroom for cheap.
INFIDELz>