I like the Modern Family series and Big Bang Theory.

I would actually recommend looking into animated movies, such as those from Disney/Pixar/Dreamworks. In animated movies, all voices are recorded at the same level, so all sound is equalized. It is much easier to hear speech as a character is never far away from the microphone.

I also second Documentaries, the narrator is always easy to understand. Although I'm unsure of what you have access to, as I'm pretty sure you don't have the History Channel or Discovery channel readily accessible.

If you like action/thriller/crime related series/dramas, then NCIS, Criminal Minds and The Castle will help you a lot. Mostly because they don't speak super fast (Criminal Minds for example). Also, they have different English accents so you can get used to listen different ways of speaking.

Something you can also do is, watch documentaries when you have nothing else to do, they speak fluently and at a average speed most of times, it will help you to improve your listening/understanding skills.

The British (and original) version of The Office!!

Supernatural is one of my favourite series, too!