Penney's game: should you pick first?

You and a friend play Penney's game. One player names a sequence of three coin flips (such as HTH), then the other names a different three-flip sequence. A fair coin is flipped until one of the two sequences appears as consecutive flips, and that player wins. Would you rather choose first or second? If second, how do you respond to each possible first choice, and what is your worst-case winning probability?