I just installed XP on my system late last year but only because Adobe Photoshop Elements and Premiere Elements require it. Then I found out Premiere requires SSE2 so now I have to buy a new processor and MB. I'd say it's going to be a very long time before "everyone" uses it. I still use Win2K Pro. It was just a few years ago that a university computer lab upgraded from Win98 to XP.
I will probably wait until next year when I buy a new computer. The 2gb of memory and 256mb graphics card recommendations will limit a lot of people wanting to upgrade. I think most people will upgrade when they buy new computers and it comes preinstalled.
Any idea when Dell's will be available with Vista pre-installed?? Right now you can only buy one and get the Vista upgrade..
It will take years just for the fact that if you bought a computer within the last year its got a good chance of not being vista compliant (ram and 64 architecture)...avg. lifespan of a comp is around 5-6 years, so it will take about that long...I knew someone 6 months ago who was still using 98 because it worked for them.