The case for Zito's contract:
Since becoming a Giant, he's gone 13-22, and has a 5.83 ERA and a 1.86 WHIP this season. His peripheral stats were on the decline before the Giants signed him, and now they seem to have caught up with him. He's lost the little zip he did have on his fastball, and as he moves into his thirties things will probably only get worse. Even if he bounces back and becomes a league-average pitcher, he'll never be worth $18 million a year. For that kind of money they might be able to sign someone who can, you know, actually get people out.
The case for McGee:
That's not enough for ya? Try this, or maybe this. What is it? Eyes that don't seem to open all the way? The 'stache? Asymmetry? Whatever it is, it's ugly.
Now it's up to you to decide. Are you going with the contract that brings the term albatross to a whole new level, or Mr. Eyes that don't open the same amount? Make your arguments in the comments.