iOS: Mailtime makes your email inbox look like an SMS chat session with added functionality for getting stuff done. The app sorts your email in an SMS styled interface, allowing you to use the @ sign to mention and assign tasks, and create to-do lists.
None of us would mind letting go of formal, lengthy emails and replacing them with SMS entirely. Mailbox integrates with Dropbox for attachment management, but also allows you to add photos from your phone. You're still able to add someone to the conversation with just a couple of clicks.
What it doesn't offer, however, is an easy way to organise mail. There's no priority system or folders to depend on for organisation. You do have a search feature, so you can quickly locate an email using keywords or contact names, but this isn't meant to be a primary mail client; it's something that can be helpful when you're in the middle of a long email conversation. Hit the link below to try it out.