The Leftovers. If I were to ever put together a top 10 list of personal favorites, this would be at the top then in a distant second I could start ranking the rest. I love how fully realized its concepts were. I love how it stuck true to its convictions right up to the end. I love the mashup of science fiction and fantasy and grief and contemporary life. I love the beautiful Max Richter score. For a show that starts pretty bleak in the first few episodes you really feel the love and warmth by the end of the series and the discovery of inner piece.
I always like to add this caveat to anyone jumping in, the first half of season one can be tough. Episode 3 is a good taste of what the show is at its best and episode 6 is one of the best in the series and the point where most people are fully hooked.