Thanks for all the suggestions guys! I see that Supernatural is a popular choice, I've seen it recommended before but never gotten around to watching it. 5 seasons? Sounds like that will keep me busy.

A lot of the series mentioned I've seen episodes here and there but never committed to any of them, like Medium, Arrested Development and NCIS which I liked but could never keep up with. I should probably check out Burn Notice, I've heard good things about that. And I've been told to watch Archer too by my brother, incessantly.