Nice after-Easter problem - Outlook 2007 in Cached Exchange Mode would crash when synchronising with the Exchange Server.
If I started it up in Safe Mode (outlook.exe /safe) it would also crash.
I reconfigured it to not use Cached Mode and it worked correctly.
I managed to fix the problem by renaming outlook.ost and having Outlook rebuild it on next start.
For Vista users, outlook.ost is located at:
and for XP users it's located at:
C:\Documents and Settings\<username>\Local Settings\Application Data\Microsoft\Outlook.