Even if you're only planning to use that notebook to send email, you still need a comfortable keyboard. Open Notepad, and type out a few sentences. Do the keys feel mushy? Are they too close together? Too small? Are you making a lot of mistakes? If you answered yes to these questions, look for another notebook.
Also pay attention to key travel, especially on Ultrabooks. Some laptop makers make their layouts to shallow in order to make their machines thinner. Another thing we like to see is direct access buttons for volume, screen brightness, etc., instead of having to press the Fn button first.