Turner Classic Movies is one of the best cable channels out there. Robert Osborne was the best. I also enjoy Ben Mankiewicz and The Essential series.
I miss Osborne but I do like the crew they have right now. Mankiewicz, Eddie Muller whenever there's a noir/mystery movie, Dave Karger and Jacqueline Stewart are both really informative, and I can't get enough of Alicia Malone.
