Oh man. X-Men had such a huge influence on me back in the '90s. Chris Claremont's storytelling mixed with Jim Lee's art was just breathtaking. I remember being a kid and ONLY having the issue where Omega Red wiped the floor with the X-Men and it scarred me for life (but in a wonderful way). Also, how they handled Morph in the cartoon (and set up stakes for a kid's cartoon) was simply excellent.
X-Men has a large place in my soul.