Depends on the draw zed - if Murray and Roddick are in the same half (as they were in Wimbledon draw) they can't play each other in the final. Your prediction is a bit premature until the draw is made.
the rankings have nothing to do with which half the players are drawn in, with the exception of players seeded one and two, who are always in opposite halves.
they will be drawn according to whatever the atp rankings are. THE USO unlike Wimbledon always duplicates the ATP, You should be old enough to know that!