Microsoft will get Outlook to perform flawlessly, without all the little idiosyncrasies that drive us all to distraction. There's no doubt in my mind that Outlook is the world's best business-user's email and contact management application bar none, but it does suffer from digital indigestion on a frequent basis.
If it's any consolation the next version - Outlook 12, which I've been using for several months now - is much improved, but it still has that red killing mist factor to some degree.
VoG™'s suggestion is the right one - try that and see what happens. If it doesn't do the trick come back and tell us - we'll try something else.