I hear a lot of talk below about how Angela Bassett should hacve been Storm. Fools. The right pick is clear. Nona Gaye. To paraphrase MF, a rather stunning sister with flows that's gorgeous.
UPDATE: One other interesting thing about Nona--she is almost literally the spawn of "Let's Get It On." Word is that Marvin wrote that song after seeing her mother--who was like 17 years younger than him. There's something cool about knowing that song produced one of the most beautiful women on the planet.