1: Tom Baker
2: William Hartnell
3: Peter Davison
4: Jon Pertwee
5: Patrick Troughton
6: Paul McGann
7: Colin Baker*
8: Sylvester McCoy
This is not to say that all the stories of the higher-ranked Doctors are brilliant or that all of the stories of the lower-ranked ones are stinkers. It's my overall impression of them.
My kids would be better judges of who is better amongst the Doctors in the new series (I don't watch it enough to judge).
* If this list included the Missing Adventures novels the 6th Doctor would most likely move up, but I have limited this to TV performances since this is the most accessible medium.