Good move by both teams, but if I had to choose, I think this is a better deal for the Nuggets. The Nuggets get Billups, who is more of a true point guard as compared to Iverson, and this will allow Melo to take the reigns of the Denver offense. Iverson will provide a spark on offense and quick hands on defense for the Pistons, but will force Rip Hamilton to move to the 3 to make room for Ivo at the 2.
The Pistons will have to eat Ivo's $21M salary for this year, since he is in the final year of his contract, and should allow for Rodney Stuckey to get a big payday from the Pistons before next year.
McDyess, on the other hand, says he doesn't want to play for anyone else but the Pistons, and may retire or engage in a contract buyout, so that will be interesting to see, even though he used to play for the Nuggets.
The season is less than a week old and already a big trade going down. Should make for an interesting season.