I depend on Outlook 2007 in a number of ways but it has been kludgy, memory-hoggish and recently, a dead weight on anything else that was running at the same time. Granted, I have a massive storage of email and use the heck out of tasks, but still, it should work once things get loaded. Today I got fed up with the freezes and did some investigation.
I am happy to report I found what seems to be a magic tonic, restoring the Outlook I used to like!
The cause was apparently an "Add-In", and the slowness is a common symptom. I won't go into all I read about Outlook Add-ins here, but it is a little subculture all its own.
The cure, for me, was as easy as disabling all Outlook add-ins... once I found where and how (it is not obvious!)
1) To do this in Vista, you have to be running Outlook as an administrator . (right click on Outlook.exe, select 'run as administrator')
2) Once Outlook starts up, go to Tools, then Trust Center
3) In the Trust Center window, select 'Add-Ins' - you'll see a list of Add-Ins, and below that a select box labeled "Manage:" Select "COM Add-ins" and click "Go", to bring up the window where you can actually Manage your Add-ins. ( They must over-engineer this on purpose. 1 out of 10 for intuitiveness, MS!)
4) In the Add-Ins window, you can uncheck the box for any that you want to disable. I unchecked them all, not seeing a darn thing there I thought I might ever need. ( And surprised at the number of things that allow themselves to 'talk' to Outlook behind the scenes)
5) Save, OK and otherwise Exit your way all the way out, close Outlook and if you like , reboot your computer.
6) Launch Outlook again like always, and marvel at the speed. Seriously, this made a *huge* difference!