I was surprised to see that SP1 for SQL Server 2005 is already available. Seems like just yesterday that the product shipped. Anyway, there are some very interesting features including database mirroring for HA scenarios and enhanced SQL Server Express support to include a GUI for managing the free edition (which MSDE sorely lacked). In addition, it appears that it is possible to host SSRS on this lightweight verion, which to me is baffling. Is SSRS now free? Is SQL Server Express a FREE replacement for access?
http://www.microsoft.com/presspass/press/2006/apr06/04-19SQLExpands06PR.mspx