While both Swisher trades didn't pan out, the Teahen contract extension was a mistake and Daniel Hudson is turning out to be a very good pitcher, I voted the Peavy trade as the worse move. Mostly for the money involved.
Jake Peavy's been a member of the White Sox organization for 1 year and 2 months of MLB service time. Over that period, $18+ million has already been paid to Peavy for a 10-6 record, 127 IP and a ERA of 4.11. Plus we're still on the hook for an additional $15M this season, $17M next year and a team option of $22M ($4M buyout) in 2013. If Peavy never wins another MLB game, the White Sox would pay him a minimum of $54M for 10 wins. Even if he returns, it's very doubtful that he'll ever return to the Cy Young winning level of his past.
Another reason is that Clayton Richard, one of the five players we trade for Jake, has done well pitching for San Diego. Since the trade, Richard has gone 20-11 pitching over 285 innings with a 3.88 ERA while earning a total of less than $525,000 during his time with the Padres. Richard isn't an ace or a #2 pitcher. He probably tops out as a #3 pitcher at best but he'd sure look good on our team right now and would allow us to easily make the decision to let Buehrle leave via free agency after this season. Richard also won't be eligible for free agency until after the 2014 season.
It would be nice right now to have another 200+IP per season lefty starting pitcher on the 25-man roster and the $15M savings left in the budget to spend on fixing the bullpen holes on this club now and in the near future.