Smalling and Jones will be the new Rio and Vidic and possibly turn out even better. If De Gea fulfills his potential then it will be a hell of a triumvirate.
Smalling is the composed ballplayer, the equivalent of Rio, but arguably better in the air.
Jones is the muscle of the operation, the new Vidic - a bit of the John Terry Lionheart about him but he has that modern CB ability to burst forward when required.
The best thing (for me) is that they will become Englands first choice CB pairing as well. Playing together for both club and country will be fantastic for them and they should develop a great understanding.