X-Factor #85 is without a doubt one of my most memorable comics experiences.
It was dark, fast, and focused on the characters. There was death, decapitations, characters actually getting fucked up, and a lat of line work. It's an issue with 50 characters in it, but each panel explains who they are and what they do without drifting off into origin stories.
I was 10 when I read it. It has stuck with me. Attached are a few excerpts, but I saved the best for those that go and read it.