I just saw two folks with an issue installing VS or Express because they had Kaspersky AntiVirus installed.
The error you see int he setup log is:
[11/07/05, 19:11:01] setup.exe:  ISetupModule::SetManager() failed in ISetupManager::LoadSetupObjectGuid() : vs_setup.dll
If that product is installed, it will hang the VS installation.
Work around is to uninstall the anti-virus before installing VS. Note - just disabling it is not enough.
For more info, check out the forum post at: http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=126688&SiteID=1