I thought I would chime in on this discussion with my first post, as I happen to be a fan of both teams.
I think that the question of most wins between the Cowboys and Dolphins is actually too close to call. I believe both teams have had terrific offseasons. I really liked the way Dallas addressed needs through the draft and free agency, and I think Miami scored their best acquisition in January with the addition of Nick Saban. They also have not been too shabby at all since then.
I think the Dolphins have the chance to have one of the most explosive receiver and running back sets in the entire league, and I give them the edge over the Cowboys in those skill positions. Frerotte is going to be a sleeper this year, but I think Bledsoe will also surprise some people, as the Cowboys line is going to give him time to find Keyshawn, Glenn and Quincy Morgan.
Both defenses are going to be stout, and both coaching staffs are excellent. I really liked Miami's move to nab Hudson Houck to coach the most troubled unit on the team last year. This guy is excellent, take it from a Cowboys fan who saw the results of his coaching week after week and also witnessed the deterioration of that line, in large part due to his departure after the 2001 season.