I'd be here awhile if I listed all of them (to date, I've seen a grand total of 1,671 feature films), but I'll point out some of the highlights:
-Of those 1,671, 538 of them were from before I was born (1980).
-I've seen all 83 Best Picture Oscar winners (including the "split decision" of 1928 with Wings for Best Picture and Sunrise for Best Production).
-On the current IMDB Top 250 list, I've seen 244 of those films, including the films ranked 1 through 214.
-I've seen all but one film (A Place In The Sun) on the AFI's original Top 100 films list and every film from their 10th anniversary Top 100 list.
To view all these films I have a Netflix subscription (mail and streaming) and I use my TiVO to record any movies I want to see. I have all the movie chanels, but I get a good bulk of them from Turner Classics. I try to stay away from AMC and the other basic cable chanels since they have the "made for TV" versions and commercials, but I will watch them if there's no other choice.
In case you were wondering, I use an Excel spreadsheet to keep track of all the films I've seen. That way, I won't accidentally watch a film for the first time twice.