Zidane has a legitimate shout at being called the finest footballer to ever play the game, whereas Cantona doesn't.
Cantona was good. But the Scum have had better foreigners since him, and whilst he was there (Keane, Schmichael, Ronaldo.)
Best foreigner the prem has seen is a tough one. I'd go for Henry as he was exceptional. But Bergkamp, Zola, Ronaldo and Schmichael all have good cases (however I just dont think it would be right to give it to a keeper, no matter how good he was.)