Not many shows leave a void behind when they end. In only 3 seasons, Deadwood left one of the largest ones yet.
Even if it's not a genre that typically appeals to you, any fans of authenticity, world building, or acting would do well to watch this show. It's a bit of a slow burn, but the pace pays off in spades. Watch 5 episodes, and if by then you're not hooked, I'll eat Timothy Olyphant's hat.