I recently moved to Vista, and it has been quite a painful experience when installing Microsoft Dev tools. I wasted quite a few days getting this to work correctly.
If you intend to use SQL Server 2005 Developer Edition and SQL Server 2005 Express, don't install it with VS2005. So the steps will be:
Install VS2005 - uncheck SQL Server 2005 Express
Install VS2005 SP1
Install VS2005 SP1 Vista Patch
SQL Server 2005 Developer Edition
SQL Server 2005 SP2
SQL Server 2005 Express Edition SP2
This will ensure that you will able to use SQL Server Managent Studio. Took me several days to get the order right. :p Had to reinstall Vista, cause my installs got fubar trying to get the install order right. I bought Acronis True Image 10, the minute I got this working right. Now I have a nice Vista image with all of my tools.
Hopefully, I don't run into any more issues so that I can get back to finishing PainlessSVN.