I just wanted to point out an app I discovered today that I hadn't heard of previously - Mailplane. It's only been sparsely mentioned in this forum, and, since topics about Gmail and IMAP seem to be constantly popping up, it's worth mentioning as an alternative. I was previously using Fluid to create a Gmail-specific app. Mailplane does the same thing, but also adds drag-and-drop attachment adding, Mac Address Book integration (sort of), and Growl notifications. I haven't used it extensively, but it does what it says fairly well. It costs $25, so I'm still not sure if it's worth it, since Fluid is free. At any rate, there's a 30-day trial.