I didn't even mind Adailus until the 3rd yr. He was actually okay in the SB year, and although hurt in 2008--he was still nowhere near some of the other mentioned signings such as Duane Starks, Monty Beisel, Chad Brown, Doug Gabriel, Joey Galloway, Albert Haynesworth etc. It wasn't until the '09 season that he became extremely disgruntled and was a cancer to the team.
If I had to pick, it'd have to be Duane Starks, due to the fact that we gave up a 3rd rounder for him. That's a pretty big swing and a miss.
Oh yeah, and who's the other more recent 3rd rounder that we lost? The guy from the Raiders...Derrick Burgess. He was another costly free agent acquisition.