Fleury was a firecracker. He put on an incredible show, but he was also a bit unpredictable. I wouldn't have wanted to build my team around him, as dynamic as he was.
St. Louis is more cerebral and consistent. He's not got that scrappiness that Fleury had, and his goal scoring is a step below Fleury's, but he's put up incredible point totals year after year.
Ultimately, I pick St. Louis. I think he's the "true" captain of the Lightning. I watched him lead his team through example and awesome individual performance to a ECF victory against my Flyers on the road to the '04 Cup and I've been a fan of his since. It's rare when you develop a love for a player while he's defeating your favorite team in the playoffs, but it's hard not to like Marty.