I was at that Saturday NYY game at RFK, and I just loved seeing Rivera blow a save in person...not that I have anything against the guy (quite the opposite, I think he's about the best closer ever, and he sure made my grandfather happy for the last few years of his life), but what an improbable game that was
But to the original question, I go with Cordero...I just can't see anyone else coming onto the scene (either through the ranks or from the trade market) who comes even close to Chief. He didn't go to the All Star game for nothing! It seems to me that the job is about 90% mental, and the ability to shake off a bases loaded, one out situation in a one-run game and go ahead and shut down the next two batters is key...and that is pretty much Chief's forte. He may be quite a bit more permeable than, say, Lidge, but he also shows amazing sangfroid under pressure. At his age, he's got all the time in the world to develop & refine different pitches.