First, the not surprising ones:
-Matthew Stafford was a 5 star, and the #2 QB in his class.
-AJ Green was a 5 star, and the #2 WR in his class.
-Tim Tebow was a 5 star, and the #3 QB in his class.
-Percy Harvin was a 5 star, and the #2 WR in his class.
-Eric Berry was a 5 star, and the #1 CB in his class.
So clearly, sometimes the star ratings and Scout/Rivals/ESPN player rankings get it right. But they also often miss the mark on some players, and sometimes players grow into stars with coaching and maturity.
-Knowshon Moreno was a 4 star, and the #9 RB in his class.
-Rennie Curran was a 4 star.
-Mohamed Massaquoi was a 4 star.
From other schools:
-Mark Ingram from Alabama (Heisman winner) was only a 3 star, and the #58 RB in his class.
-Dexter McCluster from Ole Miss was only a 3 star, and get this: the #100 RB in his class.
-Ndamukong Suh from Nebraska was a 4 star.
-Sam Bradford from Oklahoma was a 4 star, and the #17 QB in his class.
-Colt McCoy from Texas was also a 4 star, and the #14 QB in his class.
-Jordan Shipley from Texas was a 4 star and the #18 WR in his class. Nice picture by the way.
Just think, some of these guys when being recruited weren't exciting to their team's fans.
(Of course, it can go the other way too, and there are plenty of former 5 star recruits that never show up strong on the field. I'm not going to list them. But still, it's much more likely that a 3 or 4 star out there is going to make a huge impact than a 5 star that makes none.)