I had been experiencing massive delays after connecting to a TFS server in Team Explorer 2008. These usually ended up with a COM exception – Creating an instance of the COM component with CLSID {B69003B3-C55E-4B48-836C-BC5946FC3B28} from the IClassFactory failed due to the following error:80004005.
This turned out to be a problem with the October release of the TFS PowerTools. I found the solution here which was based on disabling the new ‘Collaboration’ feature that was added to Team Explorer.