Alfred Molina wins the award for most races/nationalities played the best by anyone ever!!

Wait to go Freddie!

 Prince of Persia - Persian, but not the prince

The Da Vinci Code - Italian/French?  Can't remember. 

Frida - Mexican or John Lovitz look alike. 

Magnolia - Greek?  (Solomon Solomon right?)

 The Imposters - English, I think that is from the imposters, I thought he wore a top hat in it.  

 Boogie Nights - Very Pale Drug Dealer

 Maverick - Mexican

 Species - Whatever Ben Kingsley was playing. 

Spider-man 2 - Half Robot Octopus/Half Human

Indiana Jones Raiders of the Lost Ark - Generic brown race that dies around Indiana Jones. 

 Have no idea - Albino?  Village of the Damned?

 Tevye!!!!!!

 Others Notables - 
Cabin Boy - Fancy Boy
An Education - English
Identity - American
Chocolat - French
The Man Who Knew too Little - Russian
And the winner is English!

 1st Runner Up - Cliff Curtis, and this was very close, mainly because Molina was in Boogie Nights.

 Other Runners Up - Patrick Stewart, Djimon Hounsou, Mario Lopez