Although I was thinking this would be at least 2-3 years out, my mind has changed.
Today Nvidia released a new graphics card, the 7800 series. It’s basically a good rev of the 6800 architecture. Overall the price is a bit high, but not too too high if you are in the performance game. People will move towards using that new hardware, and what is high-end today, will be common tomorrow.
These cards are looking at supporting high-resolution, wide-screen displays and having larger textures in memory. In one article they mention that the footprint should be about 144megs for a large widescreen. This means that 256meg cards are not far behind.
When we start looking at video cards with 256 or 512 megs (with 1 gig coming), we are talking about a lot of address space. Based on that, it would look like it makes sense to start moving to 64 bit OS’s in order to handle these newer cards.