****ing love this genre. Anyway, for me: 1. Once Upon a Time in the West 2. The good, The Bad and the Ugly 3. Red River 4. Unforgiven 5. The Proposition (token Australian film) Anybody else like em?
Big fan and here are a few that haven't been named yet: Utu (NZ Western ) A Fistfull of Dollars & A Few Dollars More (All awesome films, 3rd in the series is the good the bad and the ugly) The Wild Bunch (Fave non Leone or Eastwood Western) High Plains Drifter (Eastwood directing and starring in this one well before Unforgiven) I also quite like 3:10 to Yuma with Christian Bale and Russell Crowe. Dislike John Wayne's westerns though.
High Noon is a classic The Man who shot Liberty Valance is superb The Searchers is John Wayne's best Butch Cassidy & The Sundance Kid is a decent watch too. Still looking for The Wild Bunch though.
Without naming ones that have been named already. The Comancheros Paint Your Wagon Ride the High Country The Magnificent Seven
These are my top two as well in exact order. The final showdown in Once Upon a Time is epic. Tombstone is great too, with Kurt Russell and Val Kilmer.
Nobody mentioned these, The asian cinema scene have just started making some really good westerns, they're fair awesome. Sukiyaki Western Django http://www.youtube.com/watch?v=9-TGaGa3QAc The Good, The Bad, The Weird http://www.youtube.com/watch?v=OzNnCK5cd8Q