Rurouni Kenshin. There's just so much epicness, especially in Season 2. The soundtrack is amazing and the emotional/intellectual depth when it comes to the dialogue and fights and the larger themes they give substance to..well you just don't really see it in any other show, or even movie.
I'm tempted to say something similar about the TV adaptation of Tintin, but I don't think I'll go there. The show isn't quite the comics. Still great, though.
In terms of live-action, "adult" shows though haha, I've been obsessed with The Sopranos and Deadwood in the past, but now it's another HBO show, Game of Thrones. Which, alongside the books, is pretty easy to get obsessed with.