right now, it's too early to tell. The Sr. Bowl helps the seniors a lot, but we won't get a good idea where people are projected until after the combine/pro days/private workouts.
guys like Dwayne Robertson,Donte Whitner, Phillip Rivers, Jac Cutler,Dunta Robinson,Jon Vilma (was widely projected to go between 20 and 32) Ronnie Brown (was considered a late first most of the year, but rose rapidly after the combine), etc. Have risen up the boards because of excellent workouts.
Then there are the guys who fall because of character concerns (Justin Miller; mid first rounder, that falls to the Jets in the 2nd), poor wonderlic scores (Ko Simpson; late 1st-early 2nd, falls to the Bills in the 4th), or just don't have the speed to play the position they're projected to play at (Brandon Browner and Ernest Shazor went from 1st/2nd rounders to undrafted).
It would not surprise me if Anthony Spencer from Purdue was a mid first rounder come draft day, nor would I be surprised if a guy everybody wanted in the first falls to the 2nd.