True it was not in the manga and was just a filler saga but it is still part of the TV show timeline which means The Dead Zone must count as canon?
Also for the love of god do not watch Dragon Ball Evolution. Even if you want to check it out to see if it's as bad as people say, don't!
That film belongs buried in the desert with all the copies of E.T on the Atari.
Unless stated by the author, anything that isn't part of the original source material, the manga, is non canon. Even then, the thing stated as canon can't contradict anything from the source material.
While GT might be not very good, I liked a some of the characters from it like SS4, Pan(what the problem is), Baby Vegeta, Super 17, etc.
I felt that the Baby Saga went on far too long, whereas the Super 17 saga wasn't long enough. And even then, Super 17 was only in a few episodes due to them focusing too much of their attention on Frieza and Cell.
Anyway, OP, I'll say this - Just watch DBZ. While DragonBall will help explain stuff later, you don't need to watch it. Avoid GT. And for the love of money, AVOID DRAGONBALL: EVOLUTION!!! It will shit on your soul, and make your question your very existence.
Ok, not really. But still...DB Evolution is that bad.