Assuming "I'm a Window" isn't the last single, "Metal Airplanes" would be a good third single. It's an accessible track that's mellower than the previous two singles and could play up the diversity of the album and add some crossover appeal.
If there was active radio/TV promotion in the US, I doubt neither "She's In It For The Money" or (a heavily edited) "Champions of Nothing" would be very successful. I highly doubt most radio programmers would play either song on the basis of the relative inaccessibility and length of "Champions..." or lyrics for "She's In It..." (eg "I'm in love with your pills/A little red and a little blue").
