Damn, that's a genuinely hard one. trying to think about it: Which comic have I worn out, and maybe had to replace from just re-reading it over and over? AH!
Worlds Collide #1, the Milestone / DC crossover. Superman vs. Blood Syndicate, Static, Superboy and Rocket teaming up, the nerdy mailman being transformed into a pan-dimensional psycho-god, writing by Dwayne McDuffie, and art by Dc & milestone's finest? Yeah, I re-read that one comic so many times, it may fall apart if I take it out of it's bag now.