I like Thumb Keyboard:
Thumb Keyboard (Phone/Tablet) Android App Review by AndroidTapp.com | Android Tapp. Android App Reviews
It has a dictionary that learns the words you type the most. It has auto-correct in that it suggests different spellings but does not force correct on you; a feature that I like, because I put a lot of job-specific acronyms in my texts that other keyboards try to "correct". Thumb Keyboard even learns those acronyms and begins suggesting them when I start to type them. What I like most about Thumb Keyboard are the different keyboard configurations that you can set. You can even set different configurations for portrait and landscape mode.