I strongly dislike the word rational / rationality as labels for what we try to do here, because of its unfortunate Straw Vulcan connotations. Strangely, it seems to me that despite the very similar etymology, those connotations are much weaker in the words reasonable and reason. (For example, I would never think of telling someone I'm giving advice about romance “the most rational thing for you to do is [bla]”, but I have no problem with saying “the most reasonable thing” or “the thing that would make most sense”.)

I'd suggest to replace the last word in LessWrong's tagline from rationality to reason; would that have any drawbacks I can't think of?