Hm, can't really put in my vote because the option's not there--probably because what I think is not very often done with an ASCII console: both simultaneously.
Square fonts are great for the map because there's no distorsion, but they're horrible for reading text. Reading blocks of text in libTCOD games is very, very annoying. Characters are meant to be taller than they are wide, and your eyes are used to reading and recognizing shapes of words, so square-font text really suffers in parsability.
Ideally you have your map using square fonts, and the text drawn with tall fonts, though obviously this approach only works if you've got an engine that supports it. (It's also not very traditional, since console terminals can't do this.)
For a readability comparison, check out
this post I put up about the square/tall mix I implemented for X@COM. The map is still square, but text windows are all done with narrow-width fonts which make it sooooo much more readable. I've heard that Brogue is looking into taking the same approach (even though it uses libTCOD, which doesn't support that feature--don't know how they're gonna do it without a pretty significant engine refactor).
Poll