8 Best Times X-Men Joined The Avengers
7. Storm
During the Shattered Heroes storyline, the Avengers needed new blood to combat the threat posed by Norman Osborn and H.A.M.M.E.R, and one of the people they approached, on the recommendation of her husband, was everyone's favorite weather witch Storm.
First showing up in Vol 4 # 19, she was the perfect fit, with her exceptional leadership skills and ability to control the weather a brilliant complement to the other capes within the team. She would perform above and beyond expectations during her time there, helping lay the hurt on anybody that threatened the safety of the planet.
She would remain a member up until the Avengers vs. X-Men storyline, where she would leave to stand side by side with her old compatriots. This would put her at odds with her own husband, T'Challa, as he would side with Cap, Tony, et al. So much so in fact, that he would eventually annul their marriage without telling her. Class act.
When the dust had settled, Ororo Munroe would take up her familiar role back with the X-Men, but for one year or so, she was an Avenger, and a bloody good one at that.