1. Doctor Who
2. Firefly
3. Fringe
4. Game of Thrones
5. Mythbusters
All of them REALLY well made, innovative, imaginative and awesome.
I feel talkative, so here's my explanation for each:
Doctor Who: Massive, massive plot line. Huge universe. Lovable characters. Amazing writing. Brilliant actors. Fantastic music.
Firefly: Unique, made with tons of heart, the cast went together really well, the writing was amazing, music was brilliant. I curse Fox with every breath for cancelling it.
Fringe: Weird, great actors, realistic characters. I also love how it tries to explain things with science, and makes it believable.
Game of Thrones: Amazingly written, unique characters. Better than the book, in most respects. A success in almost all fields.
Mythbusters: Showing real, physical science to those who would miss it. With great hosts, a great concept, and great science, it's easily the best science--based show out there right now.