I like Apple’s clean and simple Mail application. Like most mail applications, it tries to suggest recipients as you start typing their name in the To: box. However, I find it frustrating that Mail doesn’t pull these suggested recipients strictly from the address book. Rather, it collects addresses that you use them and makes the suggestions from this list. I once mistyped a coworkers email address and from that point on Mail diligently drove me crazy suggesting this “alternate” email address at the top of the list for this recipient… each and every time (yeah, 6 or 8 times a day) that I would send this coworker an email.