During the Visual Studio 2005 product cycle, we realized we needed a tool to wipe out the final released bits on a customer's machine in case things went wrong. We published a tool that did that for CTPs and Betas but not for the final RTM bits.
I've been asked for a tool to remove VS 2005 several times the last few weeks so I figure I'll just post the link to it here:
Note - the tool is not officially supported in any way and should only be used as your last resort if you can't remove VS 2005 from your machine. It will remove all the products VS installed so some of your applications may stop working after running this tool.