Here are my thoughts on a few of the players who I am especially familiar with:
Calvin Johnson, Georgia Tech-WR: This young man will be a stud. He's got size (6'5", 235 lbs.), but we've seen with USC's Mike Williams and Washington's Reggie Williams that size alone does not matter. What Johnson has in addition is speed and athletcism that will make him a superstar in the NFL. He would have shattered records in school if he'd had a reliable quarterback to get him the ball.
Antonio Pittman, Ohio State-RB and Darius Walker, Notre Dame-RB: It strikes me that there are a lot of running backs in the NFL just like Pittman and Walker, and a lot of them are sitting on the bench. I don't think either player made the smartest decision coming out early.
JaMarcus Russell, LSU-QB: He strikes me as an even more athletic Daunte Cullpepper. His physical ability, particularly his rocket arm, will have scouts drooling at the upcoming combine, and if he hooks up with the right coach, he could be a star. I still think another year of polish would have benefitted him greatly.
Michael Bush, Louisville-RB: Stud. He should at least be a very good NFL player and could very well become a star. Strength, speed, moves, instincts--nothing not to like once he gets healthy.
Colt Brennan, Hawaii-QB: Remember David Klingler, whose records Brennan broke this year? If you do, it's not because of his NFL career. I suspect the same will be said of Brennan in a few years.
Adrian Peterson, Oklahoma-RB: Could be an outstanding running back if he can stay on the field. He did not make it through an entire college season in one piece, so I think expecting him to make it through an NFL schedule would be a reach. He's too good not to draft, but too risky to take in the first round.
Ted Ginn, Jr. and Anthony Gonzalez, Ohio State-WR: Ginn should be a successful kick returner and third or fourth receiver, and I'm not sure another year in school would have changed that. Gonzalez, however, could only have been helped by another season of college ball. He was a good college receiver, but how much did having Ginn on the other side help him? I just don't see Gonzalez making much of an impact in the NFL.
Jon Abbate, Wake Forest, LB: I'm really rooting for Abbate, the heart and soul of the Deacons' defense this past year. If anyone can be successful at a position in the NFL on sheer determination and guts, it's at linebacker and I think that gives Abbate a shot at a decent pro career.
NFL teams are greatly swayed by players measureables and performance in the combine in Indianapolis, and it will be interesting to see which of these players really helps or hurts their draft standing, and could gain or lose millions of dollars in the process.
Here's a complete list of those underclassmen who declared for the NFL draft.