iPad: While the iPhone gets a lot of attention when it comes to email clients, the iPad seems to get left out most of the time. Evomail is an iPad-only email app that takes a lot of its cues from Sparrow and offers up an easy-to-use, gesture-based interface.
Evomail doesn't reinvent email in any way. In fact, if you've used the Gmail web interface, or Sparrow on the iPhone, then you know what to expect from Evomail. The difference is that it makes use of a lot of gestures to organise and read through everything. Within just a few minutes, you'll be flipping through your messages, organising them into labels and everything else you do with email.
Evomail's simple, but it gets the job done. Unfortunately, it's only compatible with Gmail right now, but support for additional email clients is on the way.
Evomail ($2.99) [iTunes App Store]