I think I'd been reading Batman comics for all of a year when DC had the famous dial-in vote where readers got to choose whether or not Jason Todd, the second Robin, would die. I was a Jason Todd fan, and I was also a kid just getting into comics, so I didn't want to see the character get it, but I was buying comics at the grocery store and book store back then, so any comics were catch-as-catch can. Finding issues of A Death in the Family, the storyline where all this took place, were incredibly scarce, and only one of my friends got a copy.
Long story short, I didn't get my hands on the comic with the phone number until months after the event when I sat on my pal's bed and read the comics of the storyline in one, long read while he and my brother listened to Van Halen albums. I never got to cast my vote. And as close as the vote was, I always wished I'd gotten my chance to save Jason Todd.*
Then, around 2004/2005, Stephanie Brown took Tim Drake's place as Robin just long enough to get fired for reasons and then get killed (only not really) by Black Mask.
And, of course, it never actually happened, but word on the street is that DC head honcho Dan Didio really wanted to kill off Nightwing at one point during
Infinite Crisis.
A few years back Grant Morrison took over Batman and introduced Damian Wayne, the son of Bruce Wayne and Thalia al Ghul. Right out of the box, Damian seemed fully realized as a character, and - unlike most modern new inventions of characters - was in no way an awkward teenager riddled with self-confidence issues nor a Mary Sue. Pompous, brutal. Desperately in need of approval from a father figure. Everything you'd expect out of the grandson of Ra's al Ghul.
Morrison removed Bruce Wayne and put Dick Grayson in the cowl for over a year, during which time Damian put on the domino mask and the "R", and it was actually a great run on the Batbooks. Bruce returned, as comic characters hurled through space/time/realities are want to do, and we've been able to enjoy Damian and Bruce as Robin and Batman for a while.