Of course, there is gas and dust in space, and though it is very thin (in earth terms, at least), a space ship would also have to go very quickly. Aerodynamics are therefore just as important, if not more so, as they would be on Earth. Therefore, I would vote for "the shape of Sam Hornish's car from the Indy 500", because, as Marco Andretti said, "Where did he get that speed?"