Windows 7 is better but not enough
Win7 will probably do somewhat better than Vista with their corporate customers but the real problem is cost.
Corporations are loathe to spend money on something that shows no real benefit. WinXP suits them just fine and it runs everything well enough to get by. Win7, like Vista, is too expensive to upgrade, implement, and support because it requires new training, software upgrades, time, and the desire to do so. None of which companies are willing to do right now.
If Ballmer had a brain, he would come out with New XP with the following enhancements:
1) Large memory support in the 32bit version (If Linux can do it, Microsoft can)
2) Make real improvements to the interface and forget crap like Ribbons and Clown Colors.
3) Improved video support and updated Direct X like Vista has.
4) Improved networking stack. Vista attempts this but the interface is horrible.
5) No 3rd party obsolescence. Don't purposefully break 3rd party products just to force companies to buy all Microsoft. (They did this in the past and got caught, they will do it again.)
It would be an instant winner with end-users and companies. Microsoft would bury any competition and extend their desktop monopoly, unfortunately. The good thing is...Microsoft doesn't listen to their customers let alone read my comments so they will eventually fail. That will be the best thing to happen to computing.