Countdown to Infinite Crisis: The Ted Kord Blue Beetle, who'd undergone Flanderization to the point he was a Flat Character and then barely seen for a few years, is suddenly brought back in a story that highlights his positive character traits and strengths as a hero, specifically to make his death at the end actually mean something (as opposed to the characters who were C-List Fodder for the upcoming Crisis Crossover event).
Teen Titans #62: Wendy and Marvin, teen geniuses who came on during the One Year Later plotline to repair Cyborg and maintain the Titans Tower gear, generally treated like background characters until needed for hostages. In this issue, they discuss their dissatisfaction with their minor roles, adopt a dog, and are repeatedly assured by other characters that they're vital to the team's functioning. Then the dog turns into a monster that mauls Marvin to death and puts Wendy in a coma when none of the heroes are looking.
The Invisibles features an issue dedicated to the life, good and bad, of one of the nameless henchmen gunned down by the heroes in a previous issue.
Inverted in Captain America during Ed Brubaker's run, where Jack Monroe, also known as Nomad, is brought back early on to get killed by the Winter Soldier, and then a few issues later a spotlight issue reveals what he was doing in his final days before his death.
Vibe's death issue during the Legends crossover. Even though the character was absolutely hated by fans, many feel that the depth he gained in that issue managed to make his death genuinely moving and tragic.