Plaxico is another great example, but I remember the talk being that Burress wasn't welcome back to the Steelers because the coaching staff felt that Ben Roethlisberger was relying too much on just hucking the ball downfield to him and not executing the offense as it was designed.
Plaxico was on the market for an unusually long time that season, and I think he ended up settling with the Giants for a somewhat below-market contract. I think that he's one of the 5 best WRs in the NFC--really, I'd be interested to see what would happen if he and Larry Fitzgerald traded places.
But that not the WR that I'm thinking of. I can't believe that I can't remember his name! He was a little guy... maybe a former first-round pick... Ah, Drafthistory.com saves the day again. It was Troy Edwards. Well, wait. He wasn't very good in Pittsburgh, either. Maybe it wasn't him...
Also, Antwan Randle-El hasn't worked out very well for Washington.