1) The last Superman story.
2) The reboot.
3) Superman as a killer.
4) The death.
5) The long haired Superman.
6) The wedding.
7) The Blue suit.
8 ) Waid's new origins.
First off, I'd like to mention that I am currently 31 years old, and have been collecting Superman's adventures since before I could read, at least as early as 1977-78! That said...
1) "Whatever Happened To The Man of Tomorrow", was a milestone to me when it came out at age 11. It was a truly monumental story, but I couldn't help but feel so sad for the Man of Steel....loses his cousin, then Lana, Jimmy, Krypto, and his powers. As much as I was relieved that he lived happily ever after with Lois, it somewhat burned me that it wasn't as Clark Kent.
2) I was excited for the reboot. It was all over the news. I remember discussing the pros and cons of it with my dad. Despite the changes, I did enjoy "Man of Steel". However, I really wasn't thrilled with the power degradement.
3) Unforgivable. And has always been a tarnish on the current version of the Man of Steel. How can you take a character at face value when he says in subsequent issues, "Superman does not kill!", when...guess what...he did! I'm surpised it has yet to be addressed in the current "This Is Your Life, Superman" arc.
4) It was my first day as a senior in high school-English Literature. My teacher introduced herself by passing out copies of Newsday (Long Island newspaper), where on page 2 it showed the very first picture of Doomsday fighting Superman, announcing that in the upcoming issue, he was going to die. Our teacher wanted us to read that article as she explained that the theme for the year in English Literature would be "The Hero" in all of it's myriad forms. Then after reading the article, we went on to our first story and discussion of Beowolf, the super-strong hero who would do battle against the monster Grendel. The parallels were unmistakable. Overall, I enjoyed the death of Superman issue. I even played Queen's "Who Wants To Live Forever?" as I read it for the first time.
But if you want to see a really great "potential" Death of Superman battle, pick up the newest issue of Justice (#4). It had me on the edge of my seat!!!
5) Thought it was really cool when I first saw it. Hated it very shortly after that. Can't bring myself to look at it now.
6) Loved the concept, hated the story. Very disappointing.
7) Would have been mildly entertaining if it was a "Done-In-One-Issue" story, but not for as long as it lasted.
8 ) I enjoyed "Birthright", I feel that a legend that has lasted for as many decades deserves reinterpretation stories of his origin. It's fun. It's entertaining. But, as long as it rings true of the character and his trappings.