The Mets made a huge mistake when they traded for Kris Benson, but there's no reason for them to make another huge mistake by re-signing him to a multi-year contract. And, no, I don't accept justifying the trade as a valid reason to sign a mediocre pitcher to a pricey long-term deal.
The talk is that the Mets have offered a deal around $6 million per year for 3 years. And Benson wants a lot more. Everyone's acting like Benson is some sort of elite pitcher.
He's not. His ERA this year is 4.68. The NL average ERA is approximately 4.33 (based on my rough calculation). So, his ERA is about 93% as good as the league average.
How about the rest of his career? Here is Benson's ERA+ (ERA compared to league average, adjusted for ballpark, 100=average) along with my rough 2004 calculation:
1999 112
2000 119
2001 Didn't play
2002 92
2003 85
2004 93

That's a pretty clear pattern. During his first 2 years, he was an above average pitcher. After missing a whole season, he has consistently been a below average pitcher.

Next year, the Mets will probably have a rotation of Glavine, Leiter (team option), Trachsel, Zambrano, and someone else. Benson would be an adequate number 5 starter, but he's not worth the money being talked about, particularly because there are better pitchers on the market.

Here are some free agent pitchers and some of their 2004 stats, ranked by ERA (there are probably better ways to rank them, but ERA is a simple, well known stat). I'm leaving out Pedro because he will command far more money.

........ERA, K/9, BB/9, HR/9
Pavano 3.09, 5.5, 2.2, 0.6
O.Perez 3.16, 5.8, 2.0, 1.1
Wright 3.19, 7.5, 3.6, 0.5
Clement 3.44, 9.5, 3.6, 1.1
Radke 3.59, 6.1, 0.9, 1.0
Wells 3.61, 4.0, 1.0, 0.9
Ru.Ortiz 3.67, 6.5, 4.8, 0.7
Morris 4.40, 5.8, 2.4, 1.5
Wilson 4.63, 5.7, 3.2, 1.4
Benson 4.68, 5.5, 3.0, 0.7
Millwood 4.86, 7.8, 3.2, 0.9
Lowe 5.15, 5.2, 3.3, 0.7

Other than Boomer, all those pitchers are in the 27-31 age range. Benson is 29. So, age isn't a huge issue here. There are obviously a lot of free agent pitchers having much better years than Benson.

For some longer term perspective, in 2003, the only pitcher on that list that Benson had a better ERA than was Wright (who obviously hasn't had a very good career until this year). Career ERA? Benson beats just Wright and Wilson.

Getting into stats that a bunch of you will ignore, here's the above list ranked by VORP over the last 2 years (which is how many runs saved versus a replacement level pitcher):

Radke 82
Pavano 80
Wells 80
Ru.Ortiz 72
Clement 67
Perez 63
Morris 53
millwood 47
Wright 39
Wilson 24
Lowe 18
Benson 10

By the way, Esteban Loaiza would top that list by a narrow margin, although after his recent struggles, I understand the concerns about him. Still...

Anyway, to sum up my thoughts, I would need to think more carefully about this to come up with a first choice and I need to see how the market plays out to see what it will take to sign any of these pitchers. My gut says to go with Radke, Clement, or Pavano.
Those guys would actually have a chance to improve our beloved Mets.