What would you recommend as THE drama series to learn English?

The assumption is that one will, after having mastered these drama series, move abroad and start living in a foreign country in which English is the primary language.. Of course this one has basic knowledge of English and can thus study English on his own in his home country.

If you had to recommend one drama(or sitcom, whatever) series,
what would you pick as the ultimate study tool?
something you have to master at least to get by in that tough foreign country?

Actually the question is for myself, I think I will go to Canada
about an year later and I can understand pretty much….
especially what people say on
The sitcom Friends, or the Office the drama,
is easily understandable to me.

What else?
IF you are living in United Kingdom,
please recommend one of your own country for I might go there too some day…
Thanks!