Right now I think I would choose to know a large (but not infinite) number of languages. I reserve the right to change my answer if one of you is more inspired.

No; I think that might be my choice as well. Either that or the ability to breathe salt water.

Unrelatedly, if you felt like posting to LJ and yet had nothing to say, what would you post about?

Dunno. I just posted a collection of fragments that had been kicking around my brain for the last week or so, which is more or less the same thing.