Voice dictation--sounds sort of dorky but there are plenty of times I wish I could type out an email or text while driving. This voice dictation is free and works pretty well. Plus it can export to mail or text message afterwards. Oh, and it's free!
Dragon Dictation app/ Free / Featuring very accurate voice transcription & the ability to share messages via email, facebook & twitter, Naunce's dictation app is immensely helpful==as long as you're conneted to the web