If you're a web applications developer and have been enjoying ScottGu's Visual Studio Web Application Project like so many of us have, here's a tip when installing the Visual Studio 2005 SP1.
I kid you not, the SP1 install was spinning up for at least 10 minutes when I received a popup message saying "You must uninstall the Visual Studio 2005 Web Application Project before applying this Service Pack." Thankfully nothing was installed prior to that point (amazing for the amount of time that went by), and I do appreciate getting the message, but geez.
So remember to uninstall the VS2005 Web Application Project in the Control Panel before attempting to install the VS2005 SP1.