As of early, early this morning I have officially started making my way through the 4 seasons of Breaking Bad. I've seen a few episodes here and there, but never really watched through the whole thing. Just finished season 1(only 7 eps) and will start Season 2 is a bit.
Game of Thrones
Spartacus (Both B&S and GotA)
The best seasons of Lost
As of now, I think GoT is my favorite