I had a look at the SQL Server 2005 Express Manager a few days ago and realised that it works with developer, standard and enterprise editions of SQL Server 2005. I was also impressed to discover that it also works with SQL Server 2000 instances. I should also mention that you'll need to install .NET Framework 2.0 - the link is embedded on the download page at the following location: http://www.microsoft.com/downloads/details.aspx?FamilyID=8f92556a-6c3b-47d2-9929-ecdc5a4d25ae&displaylang=en
The express manager is a light-weight client, similar to QA but not as feature rich. It is a good alternative to the query edition in the SQL Server 2005 management studio (application launch time is much better in Express Manager). I just hope that a drop-down combo is added in future releases and that it also remembers server/instance name.
BTW, there are a lot of good whitepapers appearing on the public website, have a look at http://www.microsoft.com/sql/2005/techinfo/default.asp