Related on OB: Taboo Your Words
I realize this seems odd on a blog about rationality, but I'd like to strongly suggest that commenters make an effort to avoid using the words "rational," "rationality," or "rationalist" when other phrases will do.  I think we've been stretching the words to cover too much meaning, and it's starting to show.
Here are some suggested substitutions to start you off.
Rationality:
- truth-seeking
 - probability updates under bayes rule
 - the "winning way"
 
Rationalist:
- one who reliably wins
 - one who can reliably be expected to speak truth
 
Are there any others?
A good reason to take this suggestion to heart: The terms "rationality" and "rational" have a strong positive value for most participants here—stronger, I think, than the value we attach to words like "truth-seeking" or "winning." This distorts discussion and argument; we push overhard to assert that things we like or advocate are "rational" in part because it feels good to associate our ideas with the pretty word.
If you particularize the conversation—i.e., you are likely to get more money by one-boxing on Newcomb's problem, or you are likely to hold more accurate beliefs if you update your probability estimates based solely on the disagreement of informed others—than it is less likely that you will grow overattached to particular procedures of analysis that you have previously given an attractive label.