As you can see below, the NL East was the most active division in the deadline deals race, with all five teams making at least one trade and gaining and losing a total of 34 players (17 each way). But who improved the most? The focus was pitching, and the Marlins, Mets, and Phillies all made deals that could help them significantly down the stretch. I'll put more thought into this after/if I analyze the impact on each team's lineup and pitching staff, but at first glance, I would presume the Phillies to have made the best trades for race to beat the Braves. Rather than simply list all the trades that went down, I shall instead list the player movements that went down just before the 4pm July 31 deadline:

NL East	Gained:	Lost:
Atlanta Braves	Tom Martin (P)	Matt Merricks (P)
Florida Marlins	Ismael Valdez (P) Rudy Seanez (P) Paul Lo Duca (C) Juan Encarnacion (OF) Guillermo Mota (P)	Hee Sop Choi (1B) Brad Penny (P) Bill Murphy (P) Travis Chick (P) Abraham Nunez (OF)
Montreal Expos	Alex Gonzalez (SS) Francis Beltran (P) Brendan Harris (IF)	Orlando Cabrera (SS)
New York Mets	Kris Benson (P) Victor Zambrano (P) Bartolome Fortunato (P) Jeff Keppinger (IF) (player to be named)	Justin Huber (C) Ty Wigginton (3B) Scott Erickson (P) Matt Peterson (P) Jose Diaz (P) Scott Kazmir (P)
Philadelphia Phillies	Felix Rodriguez (P) Todd Jones (P) Brad Correll (P)	Ricky Ledee (OF) Josh Hancock (P) Anderson Machado (SS) Alfredo Simon (P)
NL Central	Gained:	Lost:
Chicago Cubs	Nomar Garciaparra (SS) Matt Murton (OF)	Alex Gonzalez (SS) Francis Beltran (P) Brendan Harris (IF) Justin Jones (P)
Cincinnati Reds	Josh Hancock (P) Anderson Machado (SS)	Todd Jones (P) Brad Correll (P)
Pittsburgh Pirates	Jose Bautista (3B) Ty Wigginton (3B) Matt Peterson (P)	Kris Benson (P)
NL West	Gained:	Lost:
Arizona Diamondbacks	Reggie Abercrombie (OF) Koyie Hill (C) Bill Murphy (P)	Steve Finley (OF) Brent Mayne (C)
Los Angeles Dodgers	Hee Sop Choi (1B) Brad Penny (P) Matt Merricks (P) Henri Stanley (OF)	Paul Lo Duca (C) Juan Encarnacion (OF) Guillermo Mota (P) Tom Martin (P) Dave Roberts (OF)
San Diego Padres	Dave Hansen (IF) Brad Fullmer (DH/1B) Travis Chick (P)	Ismael Valdez (P) Jon Huber (P) (player to be named)
San Francisco Giants	Ricky Ledee (OF) Alfredo Simon (P)	Felix Rodriguez (P)
AL East	Gained:	Lost:
Boston Red Sox	Orlando Cabrera (SS) Doug Mientkiewicz (1B) Dave Roberts (OF)	Nomar Garciaparra (SS) Matt Murton (OF) Henri Stanley (OF)
New York Yankees	Estaban Loaiza (P)	Jose Contreras (P)
Tampa Bay Devil Rays	Jose Diaz (P) Scott Kazmir (P)	Victor Zambrano (P) Bartolome Fortunato (P)
AL Central	Gained:	Lost:
Chicago White Sox	Jose Contreras (P)	Estaban Loaiza (P)
Kansas City Royals	Abraham Nunez (OF) Justin Huber (C)	Rudy Seanez (P) Jose Bautista (3B)
Minnesota Twins	Justin Jones (P)	Doug Mientkiewicz (1B)
AL West	Gained:	Lost:
Texas Rangers	Scott Erickson (P) (player to be named)	Brad Fullmer (DH) (player to be named)
Seattle Mariners	Jon Huber (P)	Dave Hansen (IF)