I have a free subscription to the Huddle Report, because I write for them. I don't think there's a better bargain out there than that site. THR's subscription is $9.95 for the year, while most other sites are at least $20. I don't think you can beat that deal. It may not be the best, but I think it's one of the best.
This is a good resource to see who has had some of the more "accurate" drafts in recent yearsI do like Boomer's site which is now called West Coast Draft Services because it provides a thorough breakdown of a lot of players.
And although I'm not a fan of Kiper, he is on his game. Personally, I think he puts a little too much emphasis on workouts and numbers rather than on-field ability, but I guess so many NFL scouts/GMs do the same.