I too will go with auto-crossbow for a few reasons.

1) You get it right off the bat, so you get a whole lot of use out of the thing. This also means it is useful very early, when it is a very powerful tool, relatively speaking.

2) Not as corny as the other tools. The different outfits are cute, but get old.

3) Nothing like a standard, non-type moderate damage, multiple target weapon. Useful in a pinch, or when you've been playing too long and don't want to think very hard.