PDH wrote:The OP doesn't specify that it has to be a single issue, so it's just bad tactics to pick one issue when you can get a collection or something that includes that issue plus several others.
In fact, the OP specifically says it DOESN'T have to be a single issue; single issues don't count as arcs.
If I wanted to stretch the rules, I would say Sandman, as you COULD argue it's one long arc.
But I will give you two single issues that I would have a hard time choosing between.
1) Captain America: Sentinel of Liberty #12, the final issue. It's my favorite single issue of any series.
2) If I am stuck on a desert island, I figure it'd be hard not to choose the final issue of Sandman, "The Tempest"....