Nowadays my favorite one is "FRIENDS" it is a good comedy. 

My favorite series are:

-the big bang Theory (I love so much Sheldon's irony!)

-How I meet yoir mother (Barney Stinson is brilliant!)

-The breacking bad

Also the serie that I prefer durimg my teens was dawson's creek :)

Arithmetic series.

Why Big Bang Theory is so popular? It's fully stupid sitcom with plain characters and monotonous series. Isn't it?

I can advise "Sopranos". Best serial I ever seen!