While I don't consider myself an expert on Batman, I think that the best Batman stories are the unofficial trilogy formed by Year One, the Long Halloween, and Dark Victory with TLH being the best of them. The Killing Joke and The Dark Knight Returns are also pretty good.
I really like Watchmen, but I don't really think that V for Vendetta is as good.
In terms of long running series, the ones I've enjoyed the most so far are Fables, Y: The Last Man, the Boys, and the Walking Dead (though I haven't finished the Walking Dead yet).
I also like the Cape by Joe Hill (the original story, not the extra stuff they threw in).
If I had to say what series I enjoyed the most the previous year then it would have to be the 2019 Red Sonja series. I thought it was so good that I started reading the older stuff.