I just recently started using Microsoft SQL Server Management Studio Express (SSMSE).  This free tool is intended for SQL Server 2005 databases, but it works just fine with MSDE and SQL 2000 databases, as far as I can tell.  SSMSE obsoletes the tools I have been using up to this point, namely Enterprise Manager and Query Analyzer.

Enterprise Manager is slow to open on most systems I've used.  I have a server instance with 20 databases and I can take a nap before the thing finishes opening up.  SSMSE uses demand loading of the tree nodes, so performance is a lot better.

The whole integration between Enterprise Manager and Query Analyzer has a more natural feel.  Nice job, MS!