I've had a bit of time now to work with Drupal 7. I've been playing with it since it was still pretty experimental, but I finally put together a whole site with it recently, and am pretty happy with it. It's gotten a big leg up in terms of usability - this was a major focus for this release. The basic user interface is much improved over Drupal 6, and unrecognizable if you've only been using Drupal 5 or earlier. In my opinion, the advantages some CMS had over Drupal (I'm thinking specifically of Joomla and WordPress) in the realm of usability have been diminished or even eliminated - especially in the case of Joomla. WordPress still has a usability advantage if you are creating a simple blog site. But if you're using WordPress to make a more generic website - I'd look twice or three times at Drupal 7. There are also some pretty serious under the hood improvements as well. I'm looking forward to when all of the modules that I depend on are up to speed. Some of the most important ones made it into core, and many others were released with Drupal 7. Some others are close, like Ubercart, which has a version in Beta, and Views, which surprisingly is still in Alpha. If you are running a site in Drupal 5, you need to migrate your site at least to 6, but possibly to 7, if you can. Drupal 5 is no longer supported - which means that if there are security issues, they won't be addressed. There will be no more updates to contrib modules in Drupal 5 (in fact, many modules for Drupal 5 were abandoned a while ago.) Lullabot has a nice article on upgrading your site from Drupal 5 to Drupal 6, in case your site isn't ready for Drupal 7.