I was installing Visual Studio 2008 / SP1 on a new Windows 7 64 bit machine.  I wanted to share some of the hoops I had to jump through and hope it saves you time.  The first thing I noticed was it install was pretty slow - be patient. 

The Visual Studio installed with no problems but I got to a message prompt asking me to close the machine debug manager process.  It stated that the machine debug manager was open.  I did not see any application using it and it did not give the process ID.  I ended up killing the mdm.exe process and everything went like clockwork until the end.  Hope this saves someone else a bit of time while installing!