i'll get this before you get too much snark.
people will tell you to search the forums (there's a search function), that this has been discussed in various ways a billion times. other people will just tell you to get an IRO ( www.irocycle.com
, on vacation currently) because of their service, they're awesome, and because their basic wheelset is a whole lot better than the low-end components on those off-the-shelf bikes.
as for which bike? unlike the others you listed, the langster is aluminum, and steel and aluminum ride pretty differently. what do you need in a bike? the rush hour comes with brakes, which might be nice for you. the pista is a bit trackier of geometry, which might be nice for you. what else might be nice for you? you decide.