Voted for Braking Bad. I've never really "had a TV show," so to speak. But I've been watching Breaking Bad since the very first episode, which I can't honestly say I've ever done with any show ever before, and likely never will again after it ends. Its, imo, extremely well written, with a unique plot line and really gets the most out of its cast, I've been enthralled with it since I saw the first episode. No other show has ever been able to hold my attention that consistently.
In a way, I'm glad it is ending after 8 more episodes, as it will pretty much solidify it, to me at least, as one of the best TV series ever. The small number of seasons (as well as a small # of episodes per season) and a sooner-than-most-fans-would-prefer end to the show will ensure that they can't get too crazy with it and start writing shows/plots that are just too crazy, and cheapen the show like say, The Simpsons or (from what I've heard at least) Lost.
Weeds is a pretty solid show, too and I would rank that as my #2 on this list. My old lady loves that show, and I kind of got into it here and there, although they did just do their series finale a week or so ago, so, technically, Weeds is no longer a "current" show, but it was a pretty good one.