Hmmm. Good topic.
I'm going to say my top picks for drama are Sopranos, Homeland, Breaking Bad, and Dexter. No particular order on the top 3, but Dexter would probably be 4th. Well, okay, if I absolutely must choose I'll probably have Sopranos/Homeland at the top. There've been others I've enjoyed too, but those are my faves. I almost never remember an episode number, but for some reason I remember S4E09 of Homeland as being the finest television I've ever seen.
The Walking Dead and Sons of Anarchy are kind of guilty pleasures, because they're fairly stupid sometimes, but entertaining, and of the two, I liked Sons a lot better.
There were other HBO and Showtime series that I liked and pretty much watched every Sunday, some of which received a lot of critical acclaim, but just didn't like quite as much as the ones mentioned above.
As far as comedies go, Curb Your Enthusiasm was easily my favorite.