Yesterday the people at Sitecore released the new version of their CMS. Sitecore 6 (previously called "Crestone") has lots of improvements for either the end user as for dsevelopers.
A few improvements are:
- Inline editing for editors
- .Net 2.0 Memebership support
- New and faster Content Editor
- New data types
- The new Page editor
and much, much more.
For a complete list the documentation team has released an "What's New" document. You can find it on SDN5 here
More information involving enhancements can be find at the documentation are of SDN5.