Applications that use Windows Automation APIs can significantly decrease Microsoft Visual Studio IntelliSense performance if Windows Automation API 3.0 is not installed. For example, the Windows pen and touch services can significantly decrease Visual Studio IntelliSense performance if Windows Automation API 3.0 is not installed. This update is available as a stand-alone download for 32-bit editions of Windows XP and for Windows Server 2003. The Windows Automation API is a component of the platform update for Windows Vista and of the platform update for Windows Server 2008.
Set high priorty and nosplash. nosplash being one from version past.
Make a shortcut
C:\Windows\System32\cmd.exe /c start "runhigh" /high "C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\devenv.exe" /nosplash
Your shortcut will have a msdos type icon, so edit properties of the shortcut and change the icon by browsing to devenv.exe.
After the latest win7 updates I recieved 11/10/2011 we noticed that returning from debug mode or entering it takes 90+ seconds.
After suggestion by coworker i just ran it in administrator mode and vs2010 ran 10x faster than before. Try this if nothing else works!
Try temporarily disabling McAffee if this works.