But VDM was mainly used as a right winger with Sikora or Boukhari on the left. It's just that Sikora or Boukhari are no Ajax material, thus VDM was used on the left with Pienaar as a right winger. Maxwell has been the usual lb for the last couple of seasons, but he started out as an lm/lcm.
Chivu used to be a lb in the beginning but moved to the center pretty quickly. VDV has been used as a striker of lw too. Pienaar can play rw/rcm/am, with am (the '10') being his best position imo. Heitinga used to play rb before Trabelsi came, but afterwards he replaced Pasanen/Bergdolmo in the center. O'Brien officially is an lm/lcm/dm but has been moved to lb due to competition and the need for a steady lb. He has been used as an rb too.
Vierklau (rb) - Hasn't played much due to injuries
Pasanen (cb) - Surpassed by Heitinga
Bergdolmo (lb/rb/cb) - Same here
van Damme (lb/cb) - Not good enough
Yakubu (cb/dm) - Rotation player
van Halst (dm) - Very usefull in our 2001/2002 championship, experienced hardman.
Cruz (am/rcm/rb) - Seemed talented, had injuries, went on loan
Sneijder (lcm/rcm/am) - Not a starter yet back then
De Jong (rb/lb/cb/dm/rm) - Rotation player
Winter (rcm/dm) - Went on loan, wasn't as good as expected when he returned from Italy.
Witschge (lcm) - Surpassed by VDV
Knopper (am/rcm) - Injured a lot
van der Gun (am/rw) - Went on loan, had some injuries
Wamberto (rw/lw/am) - Rotation player, wasn't good enough to really make it.
Boukhari (lw) - Bought as a talent from Sparta, never really made it
Ikedia (rw) - Went on loan, seemed promising in the beginning
Arveladze (st/am) - Used to be no.1 untill Machlas/Mido/Zlatan came
Mido (st/lw) - Used as a lw in the beginning, moved to the 9 later on. Had to leave due to problems with Koeman.
Machlas (st) - Rotation player
This is the list i could think of, hopefully i remember everything well. But i'm sure chivu or Prince will correct me .