Over at Zmalltalker, Marius Mårnes Mathiesen has a very nice post on the mu4e email app for Emacs. Mathiesen, who's used many different email programs says that mu4e is the first one that he's ever been happy with. To the question, “Should I start using it?” he answers, “If you use email, the answer is yes.”
The post is a good introduction to mu4e and gives you an idea of how it works and what its interface looks like. The other two links above are to the Emacs-Fu posts about mu4e. If you're dissatisfied with your current mail app (or even if you aren't) you should definitely take a look at these posts. Mu4e may be just what you're looking for.