If you've ever been frustrated with the default search options in Outlook 2003 or 2007, consider getting the free add-on application called Xobni (which is Inbox spelled backwards). Not only does it provide superior email search options, it builds a network listing of your contacts, and it makes finding attachments very easy. It can also associate phone numbers with contacts, even if somebody is not in your address book. Also, it provides email analytics, showing average response time, email traffic trends, and related statistics. They partner with LinkedIn for displaying profile information and pictures, and there's talk of a Facebook tie-in.