I used Mail previously, but have been doing everything in web mail for ages. I just recently decided to try a desktop client again, and started with Mail, but it just seemed too limited. Then I tried Entourage and there is no going back for me! I especially like the way that it can color-code my emails by category, and I can easily setup different views to look at my mail in different ways. But the real killer for me is that I can keep my desktop and POP server in sync by setting it so that when I delete an email in Entourage it also deletes it from the server. This way I can use Entourage when at my desk and web mail at the office, and keep everything in sync even with a POP account; I may try IMAP later if I can find a good one (maybe .Mac is going to be updated? ..hint hint Apple!). Mail supposedly has this option too but I could not make it work. And you can keep your address book and calendar in sync with the Apple variants as well.