Who's your favorite X-Man and why? What was the first story you remember reading about them?
For me, it is hands down Rogue who is my favorite. I like her for a variety of reasons, but mostly because she's a tough gal who doesn't take things lying down. If you're looking for a scrap, then Rogue will be more than happy to oblige.
My first story with Rogue was Secret Wars #3. She wasn't featured much in it, but I felt an immediate connection to her because she knew that she was hated not only for being a mutant but also being a former member of the Brotherhood of Evil Mutants, and she wasn't going to let that stop her. She was and always will be a tough girl to put down. She rocks!