I don't really tend to follow mainstream American serial, like TWD or GoT. The ones I did watch were usually superhero shows like "Heroes" and "Agents of Shield". I don't really have a favorite, as neither of those are top-notch quality.
If I have to name a favorite though, it wouldn't be an English or even a Japanese drama, it would be a local Singapore serial drama broadcast in Chinese a long time ago called "The Unbeatables". It was a really fun gambling show mixed with action, gunfights, and a 'Romeo and Juliet' kind of romance. I think my favorite aspect of that show was how it dealt with the idea of fate and destiny. These two lovers didn't end up lovey-dovey like Romeo and Juliet; they argued and fought a lot due to their conflicting families, even until the second season.
And of course, the best part of the series was watching the protagonist, who was pretty much a pseudo 'God of Gambler' like Chow Yun-Fat. He was pretty badass. And besides him, the gambling scenes were so exaggerated in action-packed formats, but it was really fun to watch them. Since I have little knowledge in gambling, it was always thrilling for me to figure out who would win.