We had a new program manager join the TFS team several months ago and the first job we gave him was combing through all the the customer cases reporting problems installing or configuring TFS to understand them and make recommendations on how to avoid/eliminate them.  One of the outputs of his investigations is a new Troubleshooting Installation of Team Foundation Server guide.  If you are having a problem installing TFS, this is a good resource to check out.  Of course, don't forget the TFS Best Practices Analyzer tool in the TFS Power Tools.  It's another really terrific resource for helping identify what is wrong with a TFS installation.

Brian