First two that come to mind are Griffey Jr & A-Rod... must've been fun to be a Mariners fan in the '90s Griffey came to mind for sure, but Trout is even better. Walks more, hit for more power, and stole almost as many bases in Trout's age 20 season(49) than Griffey did in his first 3 years(16,16,18). Arod is obviously in the discussion. Both kinda show how great you can be at 19, 20 and just how hard it is to reach what Hank, Ruth, Mays and company did. God does it make me sick that Mike Trout isn't playing LF right now for the Brewers(or RF..or CF, whatever). Eric-friggin-Arnett because the Yankees decide they have to one up the Red Sox and sign him out of the blue. But I digress. Guy is going to be a blast to watch the next 15 years. Trout's probably playing in a more difficult offensive era as well.