Given the Bucs' recent troubles with character issues, maybe this is not the right thinking, but here goes...
The Bucs currently have Antonio Bryant. If you know the name of any of the other receivers, you're either a faithful Bucs fan or related to one of said receivers. As we've seen without Bryant on the field, there's no one who's going to help the QB out if he's not in the game, which puts a lot of pressure on what can only be described as the less than elite quarterbacks currently battling for the starting job. Brandon Marshall would be a MASSIVE help on the offensive side of the ball, and will give whoever wins the QB derby an all-pro target, assuming he avoids too many multi-game suspensions for violating one of the league's various conduct policies. He also has the Plaxico-like habits of making tough catches and making his QB look a little better than they actually are (for examples, feel free to look at what Cutler's done without a #1 receiver in Chicago these last two weeks).
On the subject of compensation, the Bucs absolutely have the cap space to give him the kind of contract he's after. Also, they're in a position to acquire him for a much lower price in terms of draft picks now that the situation has deteriorated to the point that Denver would rather leave him in Colorado than let him travel.
Problems and Contradictions:
1) He's got a lot of baggage, and to make matters more complicated, here in Tampa he'd be yet another WR with character concerns in a sea of WRs and TEs with character concerns. There's no telling what kind of new dynamic he'd bring to the locker room.
2) Can the Bucs really afford to give up whatever compensation package the Broncos would want in exchange for him? Given the slightly questionable depth at a couple positions, would they be better served hanging on to the picks and filling multiple holes on the roster rather than addressing a glaring hole at one position?
3) Will his ego allow him to be #2? AB is obviously solidly entrenched as the #1... could cause problems.
What does everyone think? Worth going after?