Uncanny X-Men #9 was really interesting because you get the X-Men going up against the Avengers.

Uncanny X-Men #9 was really interesting because you get the X-Men going up against the Avengers. Obviously the Avengers were holding back, but it was still fun seeing the X-Men stand toe-to-toe with them in their first real clash. What made the issue work best for me, though, was the way they were manipulated into that fight and how all of it unfolded from there. That combination made it a very fun early crossover.