To me, the best of period movies seem to put me into a historic period. Movies like Patriot, Mountainmen, etc are entertaining and have some good scenes like some of the battle scenes in Patriot but overall they are typical hollywood product. Patriot reminded me so much of Braveheart that it was hard to really enjoy.
Al Pacinos "Revolution" has some problems, especially some of the locations, but overall it really puts you in revolutionary america. The scenes in the citys have never been done better and they were done without computer generated effects.
Other movies that seem to me like a window to a past period are,
Journey of August King
Black Robe
Last of Mohicans
Drums along the Mohawk
Kidnapped (fairly recent version with Armand Assante
Unconquered (with Gary Cooper)
Rob Roy