SQL Buddy

Nice open source IDE for MSDE and SQL Server providing similar functionality to Microsoft's venerable Isql/w with the addition of a Tree browser for the database objects and a nicer looking UI. Developed in C#, it reuses the SharpDevelop editor, so you get syntax highlighting and auto-complete, and DotNetMagic for menus and docking bars, so you get a VS.NET style interface (and a few bugs too :).