Taxi Driver is in my top 10, the 70s was a high point for Hollywood, other 70s thrillers of a high calibre include Night Moves with Gene Hackman, The Conversation also with Hackman, absolutely outstanding films. Killing of a Chinese bookie directed by John Cassavetes and starring Ben Gazarra who played it kind of funny, but was a serious role, I really don't think actors these days have the same naturalness as these guys, he was amazing. Another fave from the 70s is 'Cutters Way' - do make an effort to seek that one out, it really is very special, starring Jeff Bridges, its actually from 1981, but looks and seems like a 70s film. I like 40s/50s thrillers too like Maltese Falcon, and Billy Wilder films, especially Sunset Boulevard, black and white was an art form. I think the 80s were rubbish, until the indies came through. I had the pleasure of watching most of these films at the southbank in London on the big screen at the BFI.