The episode you saw was called "Rose", with the Ninth Doctor, and is technically the first episode of New!Who - which is Doctors 9, 10 & 11. Classic!Who started in 1963 and stopped in 1989 with the Seventh Doctor - not including the TV movie in 1996, the only time you see the Eighth Doctor. New!Who started in 2005 with the Ninth Doctor - season 1 - went onto the Tenth Doctor - seasons 2, 3 & 4 - and the most current is the Eleventh Doctor - seasons 5 & 6. Technically Classic and New could be classed as two different shows in a way. So, if you want to trudge through the 26 years of Classic - starting off black and white and going into color, the adorable effects and such - then I believe you should start with the episode "An Unearthly Child", first episode ever of Doctor Who.