I've been running vista on the laptop I bought last year because it came with it. It hasnt been bad persay. It's just been kinda "meh". You look at the front end UI of OSX and vista is archaic in comparison. I, personally, want more customizability in the UI. I know I can always go to stardock and buy some, but that still isnt 100% custom to me. And I dont want to have to learn to code windows just to do something that should be built in and readily available.
Further, the sidebar in vista is ok at best. It's quite buggy and gives me issues far to often. That coupled with the inability to move it where I want makes it more tedious then its worth.
I guess those are the only things vista really has in terms of what the user sees. MS is going to have to load all the features that people want at one standard price if the new windows is going to be successful. It's also going to have to include some version of office. Maybe just a stripped down version of word, excel, and powerpoint. Theres nothing worse then getting a new computer, setting it up, and trying to open a document a friend sent you only to find out you dont have that software. MS works does not count because it doesnt read word files (at least it didnt last time I checked but that was a few versions ago).
People are getting smarter and wiser when it comes to purchases. Couple that with a staggering economy and MS is going to have to come out with a pristine product, loaded with useful, pretty, and highly desired features, both front end and back end, at a reasonably low standard price in order to be successful. Minimal bugs, decent security (no holes in the OS) and no bloat ware. It's going to have to be optimized significantly over vista. And its going to have to start offering more services that are useful, that people will actually pay for (not just windows live). Can the advertising and make people actually want to part with their money for a useful service.
Thats not to say that they should charge for tech support. Maybe they could simply have something where all of their products are available for a monthly fee. So you get full office suite for $30/mo or something. Download and play all of their games for a similar fee. Things like that would not be a bad thing in general.
MS needs to focus on the touch screen as well. There is very little software that works effectively on the tablet notebooks. Why not branch into that potential market. Businesses could benefit greatly from their employees having wireless meetings throughout their buildings, all doing their respective projects, but being able to have the whole meeting audio to text automatically, while reserving the screen for individual camera segments so that everyone can see the others in the meeting. Computers have the power, now they just need the software. Netmeeting is a very basic software from what I'm thinking of. I'm just thinking of how great windows could possibly be.
And greatly reduce these "permission to do something that I just clicked from my mouse through my own USB port yada yada" windows. Enough said.
Anyway, those are just my thoughts on the OS. I really hope MS doesnt botch the next windows. It has so much potential if they actually realize what real people want. Apple realizes that to a greater extent then MS, but apple runs very little in comparison to windows. Sooner or later that is going to change and windows will become secondary if it does not keep up.