The Doctor

First incarnation: William Hartnell [Richard Hurndall in The Five Doctors ]
Second incarnation: Patrick Troughton
Third incarnation: Jon Pertwee
Fourth incarnation: Tom Baker
Fifth incarnation: Peter Davison
Sixth incarnation: Colin Baker
Seventh incarnation: Sylvester McCoy
Eighth incarnation: Paul McGann (maybe)

The Companions

Carole Ann Ford as Susan Foreman
Jacqueline Hill as Barbara Wright
William Russell as Ian Chesterton
Maureen O'Brien as Vicki
Peter Purves as Steven Taylor
Adrienne Hill as Katarina
Jean Marsh as Sara Kingdom
Jackie Lane as Dodo Chaplet
Anneke Wills as Polly Lopez
Michael Craze as Ben Jackson
Frazer Hines as Jamie McCrimmon
Deborah Watling as Victoria Waterfield
Wendy Padbury as Zoe Heriot
Caroline John as Liz Shaw
Katy Manning as Jo Grant
Elisabeth Sladen as Sarah-Jane Smith
Ian Marter as Harry Sullivan
Louise Jameson as Leela
Mary Tamm as Romana (first incarnation)
Lalla Ward as Romana (second incarnation)
Matthew Waterhouse as Adric
Sarah Sutton as Nyssa
Janet Fielding as Tegan Jovanka
Mark Strickson as Turlough
Nicola Bryant as Perpugilliam Brown
Bonnie Langford as Melanie Bush
Sophie Aldred as Ace