How about -->
1) a completely user-defined environment OS where you could shift your computer's resource management to and from certain tasks on the fly - say, donate the bulk of your CPU to rendering filters in PhotoShop? I don't like having to hit ctrl+alt+del, processes, set-priority to get 1 program to realize it is going to need a bunch more of the CPU than an "average" program. (Yes, I know you can set RAM in prefs in PS, but that's just not enough fine control dammit! - especially if its going to lead to a crash down the road.
2) I want to see an ability for desktop visualizations which are currently resource intensive (cursorxp, cleartype, streched 300+Kb wallpapers, resolutions above 1024x768, multiple desktops, etc) to have support on graphics cards - not constantly sapping the CPU. (Lots of people now have 16Mb+ graphics cards and most of the time the cards never get worked.)
IMHO Microsoft has PAWNED OFF ITS RESPONSIBILITY to make its own GUI 2D effects widely supportable by most graphics card manufacturers for far, far too long.
When you heap on top of this the fact that these companies must pay through the nose to get MS certified certs on updated gfx card drivers its a wonder that we have any drivers at all.
(pause rant)
(drinks a glass of water)
3) and oh yeah... open source code.
- ash