Death of Superman was quite frankly the Lord of the Rings of modern comics: the greatest story told in the modern times.
It was damn good. So groundbreaking and a tale that everyone could get into. If anything, it was a knock on all the 90's anti-hero trend and it reminded people of why Superman is so important to people.
I'm partial to The Dark Phoenix Saga myself. Easily the best love story ever told in the genre. I cried after it was done, it was that good. Yeah, I'm a wuss.