Here's the OP's list, with my choices --- after his.
Atlanta Hawks - Dominique Wilkins --- Wilkins
Boston Celtics - Bill Russell/ Larry Bird -- Russell
Charlotte Bobcats - uhh.. Emeka Okafor? -- Gerald Wallace
Chicago Bulls - Michael Jordan -- Jordan
Cleveland Cavaliers - Lebron James -- LeBron
Dallas Mavericks - Dirk Nowitzki --- Dirk
Denver Nuggets - David Thompson --- Alex English
Detroit Pistons - Isiah --- Isiah
Golden State Warriors - Wilt Chamberlain -- Wilt
Houston Rockets - Hakeem Olajuwon --- Akeem
Indiana Pacers - Reggie Miller --- Reggie
Los Angeles Clippers - I don't even know.. ---- McAdoo who played for this team for 4 1/4 seasons when in Buffalo. An actual Clipper would be Brand
Los Angeles Lakers - Magic Johnson -- Magix, with props to Jerry West
Memphis Grizzlies - this is a tough one.. Pau Gasol, I guess. -- Gasol
Miami Heat - Dwayne Wade -- Mourning, but Wade will pass him if he stays there
Milwaukee Bucks - Kareem Abdul Jabaar -- Kareem
Minnesota Timberwolves - Kevin Garnett -- KG
New Jersey Nets - Jason Kidd --- Dr. J.
New Orleans Hornets - Chris Paul --- CP
New York Knicks - Willis Reed -- Patrick Ewing
Orlando Magic - Shaquille O'neal -- Shaq
Philadelphia 76ers - Moses Malone -- Dr J.
Phoenix Suns - Charles Barkley -- Charles, or Paul Westphal
Portland Trailblazers - Bill Walton -- Walton or Drexler
Sacramento Kings - Chris Webber -- Oscar Robertson, in Sacto, either Webber or Mitch Richmond
San Antonio Spurs - Tim Duncan --- TD or David Robinson with a nod to George Gervin
Seattle Supersonics - Gary Payton -- GP
Toronto Raptors - Vince Carter -- Sadly VC
Utah Jazz - John Stockton -- Stockton to Malone
Washington Wizards - Wes Unseld -- Unseld or Elvin Hayes