Diego Milito and Silvester Stallone.
You know this one.
Michael Ballack and Matt Damon
Diego Maradona and Antonio Banderas
Fernando Torres and Bruno
Julio César and Buzz Lightyear.
Xabi Alonso and Jason Bateman ("Juno" and "Up in the Air")
Ronaldinho and Jar Jar Binks. Mean!
Gerhard Delling and Günther Netzer. For all non-germans: These two guys present and discuss international matches on German TV channel ARD. They keep on fighting and bitching. They seem to hate each other and I hate them too.
There were more Doppelgängers in the source but with German "celebrities"
Have you got any more?