The best TV show I've ever watched is The Wire. I usually don't have a definite favorite when it comes to anything, but The Wire is uniquely good. It will ruin every other show for you. I tried to get into Breaking Bad, but it felt like a soap opera in comparison to The Wire. Even the Sopranos, which was excellent, didn't come close to The Wire for me. There is an older topic about TV shows here, and City Wok and SoLoD both felt the same way about it. It is also Barack Obama's favorite TV show, if that's any endorsement. The acting is excellent (many popular actors got their start on the show), the story is excellent and feels real, partially because the writers are basically writing in their personal experiences, it's often pretty funny, and the topics it covers are engaging and it will change the way you look at the world. I can't think of U.S. politics without something from The Wire coming up. It's a little hard to get used to at first, but by the 6th or 7th episode, you'll be hooked. I watched all 60 hours in two weeks... I couldn't stop. I'm now rewatching it. I can't recommend it enough.
In terms of movies, I really enjoy the Coen brothers' movies, like No Country for Old Men, Fargo, etc. Vertigo and other Hitchcock films are very good too. The Godfather trilogy is amazing. Silence of the Lambs is very good. Doctor Strangelove and Airplane! are very good comedies. The Third Man is one of my favorite black-and-white films.
Others:
Taxi Driver
Chinatown
The Great Escape
Office Space <- required viewing if you work an office job and/or are in software
Goldfinger
