I think the best one-line I ever came up with was just two words long...

I was being interviewed for a job by the President and Vice-President when they decided to ask a physcological question (I guess they must have read some book that said they should). The point of those is to see how you react as much as what you answer. This is what they asked...

"If you were stuck on a desert island and you could have one thing with you, only one thing...what would it be"

I replied...

"a boat"