JFF for the entire SEC... but to take it a little further.
LSU - can't pick just one out of Landry, Beckham, Mettenberger, Hill
A&M - also glad they lost Evans, he was a beast
Auburn - Robinson, top notch offensive linemen are always the hardest to replace
Arkansas - Swanson, same reason as Robinson. Also had a FB drafted - I didn't watch them any this year, but I assume he was an important part of their running game.
Alabama - AJ McCarron, there may have been higher picks but he should be the toughest to replace
Vandy - Matthew, almost 3,000 yards receiving the last 2 years
UM - Moncrief