Ah well they've already been mentioned, but it would have to be Jeremiah Johnson or the Northwest Passage for me all the way .... even 'persuaded' the missus to watch Johnson the other week, and despite her protestations she loved it! And as for Northwest Passage I'm still just waiting for it to be released on region 2 DVD!!!
I almost forgot, perhaps one of the greatest 'unknown' outdoorsy films I've ever seen .... "Dersu Uzala" based on a true story about a Russian explorer who comes across a grizzled old hunter .... absolutely outstanding!!!!!!!!
Northwest Passage
http://stagevu.com/video/nuskrwbvydfc