#3 Best: Cubs Acquire Kenny Lofton and Aramis Ramirez from Pittsburgh
Back in 2003, the Cubs would swing a deal that would bolster their chances in the playoffs significantly and add a pair of fan favorites. Although not remembered quite like the highway robbery that was Brock for Broglio or Strop and Arrieta for Feldman, nabbing Aramis Ramirez and Kenny Lofton from the Pirates was arguably the most lopsided trade in the Cubs' favor.
For the cost of only Mike Bruback, Jose Hernandez, and Bobby Hill - all of whom would be out of Pittsburgh by 2005 - the Cubs got their answer at third base for the next eight years along with a stellar veteran who was crucial to their postseason success. Ramirez began well enough with a 106 wRC+ in 2003, but he'd blossom afterward with a .297/.359/.533 slash line and a 128 wRC+ from 2004 through 2011 with a pair of All-Star nods and a Silver Slugger.
Lofton, who's also a brutal Hall of Fame snub, was excellent in his half-season on the North side with a .327/.381/.471 line, good for a 121 wRC+ at age 36. He wouldn't lose much steam in the postseason either with a .308/.368/.346 slash line across the team's run. Even if he didn't stay beyond 2003, he still made an impact as one of the Cubs' best rentals in their history.
Though the Cubs didn't get their World Series in 2003, the pickup of Ramirez and Lofton hit the perfect blend of short term value while setting up for the future. This team has had several deals blow up in their faces, but when they've gotten them right as they did here, they've prospered well beyond that year's trade deadline.