You can see that Microsoft is aiming to fine tune this release as the case in XP rather than technological advancement as in 2K. Highlights include "network aware", with improved connection tools and detections. It will have the ability to detect which network you're in and switch your settings and devices accordingly; With Live account, you can carry your IE settings and favorites with you; Gadget data caching; New Calculator, Paint, and WordPad using WPF; install to desktop in 10 mins with only 1 reboot; instant streaming; better battery mileage, etc.
To some extent, Microsoft's silence is to be expected. Vista has only been out of the gate for a year, and Server 2008 has yet to drop. Why get customers all riled up about a new OS so far away, especially since Microsoft has such a bad track record at forecasting ship dates? Yet if Windows 7 is truly several years away, it would seem to be in Microsoft's interests to say so. Customers might be more willing to make the switch from XP to Vista if they know that Windows 7 won't ship for four or five more years.
Yet the rumors about Windows 7's delivery are pointing in the opposite direction -- it's supposed to be arriving as early as the second half of 2009. Given Microsoft's track record with delivery dates, a lot of you probably just laughed so hard that coffee came out of your nose; I'm sorry. Even if Microsoft is simply aiming for that date but misses it by a year, its silence makes a lot more sense. If Vista's successor is just around the corner, more companies will stay with XP; that hurts Microsoft in the near term.