1 or 2 Year Master's Program
I would normally choose the two-year program, for exactly the reasons that you cite. One of the few reasons why I would consider the one-year program is if there is a particular individual you want to work with, or if it is your first-choice school for the PhD program and it offers a path of lower resistance to already be a student there.

Otherwise, as JeffE points out, you won't really save much time by going to the one-year program over the two-year program. (Besides, if it's a coursework-based program, you'll probably get more out of the two-year deal!)