I've played several systems and I can only say that I have very few.... Notable titles such as Gary Gygas's "Dangerous Journeys" where it takes 2 hours to make a single...fighter character. Also the game I believe it was called Amber a diceless system as well as the original Travaller system, where you could die in character creation. That being said.. from the systems I do play, I tend to go for those with the best story/backdrop. If it has something I can intergrate into my campagin I do so as it makes for a richer setting for my players. I have added anything pretaning to atlantean setting to Pathfinder as Azlinti are basically the same thing.
Movies also provide classes/races to be emulated such as the story behind the Tarakian from Heavy Metal. It is a positive energy being that is mute/sterile that relies on psychic warrior style class and a very limited amount that can be worn/carried. Or the paladins from the Dragon Magazine, one for each alingment; again updated for Pathfinder.
Well you get the picture, if I need story for Lycans I go to WW for tribes or if I want gothic horror its Cthulhu mixed with Ravenloft.