I have been a big fan of Matt Waldman's ever since my son introduced me to his work 6-7 years ago. My son is a huge fantasy football player, and happened across Matt Waldman's work through various fantasy football websites. Ever year Waldman puts together the Rookie Scouting Portfolio, a publication breaking down the drafts skill position players.
Probably my favorite thing about Waldman's work is the attention to detail. Not only does he provide you with clear rankings, he gives you literally hundreds of pages of observations and rationale behind his rankings. While I don't always agree with the rankings, you cannot argue with the amount of effort goes into the RSP.