Griffey at one point was not just the best outfielder in the game, but the best player. He was the next Willie Mays before injuries killed his athletic ability.
Moss is the most gifted receiver ever in the NFL but he still takes a back seat to Jerry Rice because Rice was never a known quitter who would throw temper tantrums when things didn't go his way. Also, Rice was still an effective player even when he was old and slow, Moss fell off a cliff as soon as he was no longer the fastest player on the field. At his peak, Moss was indefensible but too much inconsistency throughout his career for me to say he's the best.
Iverson would probably kill it in today's game where you can't put your hands all over the man your guarding. Still, the thing he gets the most credit for (taking a pretty crappy Sixers team to the finals) is the same reason he put up incredible numbers. In terms of efficiency, he was terrible. He was purely a volume shooter and scored a ton of points because he took a million shots. I'm sorry but a career 42% shooter doesn't belong among the all time elites. If he had played on better teams, he might have won more but his usage would have gone way down along with his individual statistics.
Get Michael Vick's sorry *** off this list. 100% bum.