A lot of these are recently or currently active players but I'm young ang I tend to always associate with the younger, current players. A player/coach has to be very special to leave an impact after retiring...
Football - Eric Cantona, Bryan Robson, Paul Ince, David Beckham, Paolo Maldini, Roberto Baggio
Tennis - Goran Ivanisevic, Lleyton Hewitt
Cricket - Michael Atherton, Shane Warne, Ricky Ponting, Michael Vaughan, Andrew Flintoff, Chris Cairns, Jacques Kallis, Stuart Law
Rugby Union - Jason Robinson, Jeromy Guscott, Richard Hill, Jonny Wilkinson, Clive Woodward
Rugby League - Andy Farrell, Martin Offiah
F1 - Michael Schumacher, Alain Prost, Ross Brawn
Rallying - Carlos Sainz, Colin McRae
Snooker - Steve Davies, John Higgins, Jimmy White
Ice Hockey - Eric Lindros, Steve Yzerman, Nik Lidstrom, Scotty Bowman
Golf - Sergio Garcia, Sam Torrance
Track & Field Athletics - Linford Christie, Maurice Green, Kathy Freeman
Basketball - Kobe Bryant
American Football - Troy Aikman
Baseball - Mark McGwire, Alex Rodriguez
Cycling - Lance Armstrong, Jan Ullrich
Swimming - Ian Thorpe