Best Olympics film? No contest. The gold goes to Leni Riefenstahl's masterful Olympia (1938). the movie that invented the visual grammar of the sports movie and eroticized athletes with its caressing closeups of rippling muscles and heroic framing of competitiors by digging trenches for the cameras, looking up worshipfully at the athletes and framing them against the infinity of the sky.
Best Winter Olympics film is a trickier question. The first three images that come to mind when you say Winter Olympics and movie feature are perky real-life Norwegian Olympian Sonja Henie ("Pavlova on Ice") as a Swiss Olympics skater in One in a Million (1937), Robert Redford as the arrogant title figure in Downhill Racer (1969), selfishly ignoring the team-spirit sermons by coach Gene Hackman, and Kurt Russell as Herb Brooks, the inspirational coach behind the U.S. Hockey team's 1980 "Miracle on Ice" in Miracle (2004). Then there are Ice Castles (1978), about the blinded Olympic contender Lexie Wilson, and the unlikely-but true Cool Runnings (1993) about the 1988 Jamaican bobsled team.
I'd probably give the gold to Miracle, the silver to Downhill Racer and the bronze to Cool Runnings. But I must confess that I really enjoyed The Cutting Edge (1992), in which a cutthroat hockey player (D.B. Sweeney) and dainty figure skater (Moira Kelly) team up to go for the gold.