This weeks homework from @missy and @rambo is what would be your superpower and why.
I would have to agree with @missy and say teleportation.
In her blog she writes about planes and traffic, definitely a good reason to teleport :p
The main reason I would like the ability to teleport (or aparate for the HP fans), is because I am always late! I set my alarm clock 10 minutes ahead because of my lack of will power to leave on time. It's a bit ridiculous.
What would I do if I had this power? Probably a trip to Manchester, and then to Universal to visit Hogsmeade<3
Other good reasons include: You'll never have to worry about driving drunk (or driving in general), you can spend the night in a different country, great way to escape a burning building, you can play awesome pranks and leave awkward situations easily.
Those are the only reasons I can think of at the moment, but I'm sure you guys will come up with some great ones! Other than teleportation, talking to animals and/or invisibility would have to be my second/third choice.