On the right side is a link to a very good article which includes a draft value chart.(addendum.. the NFL took down the article from its site, but the values are available on the February 25, 2008 posting linked here.)

We cannot change the past. Manning is our QB. Let’s be fair to Accorsi and look at the numbers. What is a first round choice worth? If you answered 1000 points, the value for the 16th selection, that is incorrect. If you answered 975 points, the midpoint of the 16th and 17th pick, you are getting closer, but you are STILL incorrect. The correct answer is 1157. That is the expected value of the 32 picks (summed and then) divided by 32. We need to know that because the Giants gave up the next year’s #1. But is THAT fair either? We are talking about a 4-12 team, a new coach, new schemes the players will need to use, and likely a new QB that will not be sending his team to a winning record. Without stats for the next year’s record (or better yet, the draft spot) of a 4-12 team, we can fairly assume they will be something like 6-10 and get the 12th pick. That falls at 1200. And considering that #13 is 1150 (7 points BELOW our 1157 math), I think 1200 is fair. Add the #3 pick at the same position (210), this year’s #1 and #5 (1800 +40), and your total is 3250. The Giants received 3000. So the Giants overpaid by 250, which is equivalent to a high 3rd rounder.
Fwiw, if you used the 16-17 midpoint, your sum is 975+187+1800+40= 3002. I would not be surprised if this is how Ernie botched, er I mean added it up.