One could argue that the L in CAN SLIM is the lynchpin of IBD's investing system. It stands for leaders -- the best stocks culled from thousands on offer. Finding just a handful of true leaders in the early stages of their big run-ups can bring great wealth to the disciplined investor. Baidu (BIDU), Apple (AAPL) and Alexion Pharmaceuticals (ALXN) are just a few recent examples of top stocks that racked up huge returns. "The top one, two or three