My favourite show all time has been since I fist watched it the sadly short lived series Firefly.

Other than that I have enjoyed Game of Thrones and will be reading the books when I have the free time because of it.

South Park is also a fantastic series that I feel has just become better over the years.

Futurama also deserves a worthy note and is something I can watch again and again without ever getting bored

There are plenty more that I find fantastic moving from history/ documentaries to action and comedy but those are the ones at the forefront of my mind.