Barry Norman reviews the best films and performances of the year 1991: ''Cyrano de Bergerac'' with Gerard Depardieu, ''Dances with Wolves'' with Kevin Costner, ''The Silence of the Lambs" with Anthony Hopkins, Jodie Foster, "Robin Hood: Prince of Thieves'' with Alan Rickman, "Thelma and Louise" by Ridley Scott, with Susan Sarandon, "Reversal of Fortune" with Jeremy Irons, "The Commitments", "Misery" with Kathy Bates, "Q&A" by Sidney Lumet, "Hamlet" by Franco Zeffirelli, with Mel Gibson, "The Nasty Girl", "Riff-Raff" by Ken Loach, "Life Is Sweet".