Those are three that come to mind. I renamed the tourstart.exe executable (tourstart.exe.disabled). I ran the above script for messenger. Not sure about the Windows Update nag.

I hate shit that moves. Always have. Discovered "clippy" (though as a puppy) in the file search function. Most annoying thing -- if you select the "f!@# yourself and die" option, you still have to look at this annoyingly cute "walking off into the sunset" animation. Shit. Least they could do is drop a f!@#ing anvil on the damned thing.