I've been doing a bit of playing around with Drupal 7 in my copious spare time (not a whole lot of that!) I've also been keeping track, a bit of how the development process is going, and what things will look like. One thing to say - it feels like as big an improvement as Drupal 6 was to Drupal 5. Of course, mostly, Drupal is only as good as it's contributed modules (that's a bit more of a stretch, now, because many of the key contributed modules, like CCK, are now in core Drupal.) So when folks like us, who build sites that depend on Drupal 7 can start using it is a bit up in the air, although there is a movement to get many modules ready for Drupal 7 at it's release. But some may well not make it. We're guessing that we'll start building production sites in Drupal 7 starting in late summer, early fall, depending on requirements. A note: the standard process for deprecation of old Drupal versions is that when a new version of core comes out, the one two versions back stops being officially supported. So Drupal 5 will no longer get security updates and the like. Already, many module developers have stopped supporting versions of their modules that work on Drupal 5. (The salesforce module maintainers recently made that decision, as have others.) So certainly a site running Drupal 5 won't stop working, but it will become vulnerable without security updates to core or modules, and it will get increasingly difficult to maintain and add features to. So it might be a good idea to budget the time and money to upgrade as soon as possible if you are on Drupal 5. If you are on Drupal 6, you've got a while yet, but Drupal 7 certainly has some great advantages, particularly in user experience, to look at.