Mailplane.app - Well Worth the Money
I’ve been using Mailplane.app for a while and I think it’s one of the best email application out there for the Mac. Mailplane.app combine the power of GMail with the ease of use of a desktop application(although in order to use Mailplane.app, a active internet connection is require). Mailplane.app has iPhoto/Address Book integration, drag-n-drop support for creating attachments, alone with many other features.
While Mailplane.app is still in beta, you can already purchase a Personal License for $24.95, or with family option for an additional $8. And as an added bonus, if you purchase a license right now, you get the family option for free which allows 5 additional people to use Mailplane.app. I can’t seems to find a link to their store on he Mailplane.app website, a direct link is hare.