7 players who have appeared in All-Star games, and 3 future Hall of Famers changed hands, but that's not what makes it the best trade deadline ever in Major League Baseball.
Only one thing really matters. Yes, the Yankees acquired a Hall of Fame catcher. Yes, the Angels got better and will now win the World Series. Whatever.
The only thing that matters is Manny Ramirez is no longer on the Red Sox. He's gone. Manny being Manny (read: Manny being an immature douche) is over. But more importantly, the utter torment and pain he has inflicted on my precious Yankees has finally ended.
Here is what Manny Ramirez has done against the Yankees for the last 3 years (167 at-bats):
a .407 batting average, a .772 slugging percentage, 17 home runs, 46 RBI, and an on-base percentage of .510. If you project that out to 500 at-bats (a typical season total), that translates into 50 home runs and 140 RBI.
I didn't know those numbers until I looked them up, but I didn't have to. I know from watching the games that ManRam absolutely creams us everytime he plays us, the same way you can tell who is winning a fight without counting punches. One guy looks fine, and the other guy is bleeding from the nose and mouth and part of his ear is missing. The Yankees never came out looking fine.
If I was a Red Sox fan, I would be furious. Manny owns the Yankees so hard, he should change his last name to Steinbrenner. And you gave him away, and along with it any chance to continue to compete with your arch-enemies. Jason Bay? Playa please. He was only an All-Star cause Pittsburgh had to have a representative by rule. You might as well have traded Manny for Pedro's midget.

And now he's gone to the National League, never to be heard from again.
Best trade ever.