If you will recall, when windows 95 came out, it's requirements drove people to upgrade their hardware, which in turn sent the prices down a lot (especially RAM). Although this sucked when you HAD to upgrade to get it to run decently, in the long run, it benefited all of us. I don't know if you remember RAM prices before that, but it was huge. I remember paying $400 for 16 megs.
Nowadays though, I don't think it can knock prices down as much of course (if at all). I will fight this upgrade as long as I can, just like I did XP, until games finally won me over (they seem to run better under XP).
Then again, maybe it'll knock down the ridiculously high price required to purchase video cards capable of running 3D games at a decent resolution/framerate. The last nvidia card (I got burned on) I bought for around $200 (CND) was such a piece of shit and couldn't run anything (Geforce 5600 XT). Part of that was my fault though, as I assumed XT was a higher version then just plain 5600. Although I am still mad at nvidia for their fucked up naming conventions. The card I had before this was a ti4200 8x, which was a hell of a card for the time, at basically the same price. Incidently, the ti4200 outperforms the 5600xt by quite a margin.
I do have a radeon 9800 Pro as well, which cost me a small fortune ($400 CND), which is now showing it's age, and I have no idea which way I'd go to get better performance without costing an arm and a leg. I think both Nvidia and ATI are releasing too many products these days, with too many different naming conventions intentionally so they can confuse the buyers.
anyways, hopefully vista will make better video cards come out cheaper.