I have only watched 5 episodes from Season 1, but Christ it's good. It has the perfect 50s/60s American setting and all the neat references of literature and dramatic irony you secretly demand, plus the characters are just so dang interesting. In fact, I'm not sure whether it was intended this way but the fact that there's not really any loveable characters makes the show feel overly oppressive.
I guess there's Peggy, and to an extent Mrs. Draper, that sort of house some form of hope for humanity, but then again the fact that there aren't many nice people is what makes it so entertaining.
Verbal symbols (memes? bit of a buzzword atm) are awesome also, it's chock-full of them. There's been some truly fantastic scenes, ones that don't consist of much, but ones which subtly give the characters a lot of depth.
Generally awesome so far, and in places quite touching.
"Who is Donald Draper?"