Oh well, while it's still open, I might as well throw my hat in the ring:
DB - The original and most closely related to the Monkey King legend. Had a lot of funny gags and stuff that would be very hard to translate into English without some prior knowledge of Akira Toriyama. THANK GOODNESS Dr. Slump is FINALLY being released in English! THANK YOU VIZ! (I always loved that series!
)Anyway, the action stuff never really caught on until midway through the series, and now here's the kicker!
In Japan, both Dragon Ball AND Dragon Ball Z were running at the SAME TIME! That's right, sometime after DB got into circulation, DBZ starting running alongside it, and it caused some confusion amongst the masses until DB started leading into what would be DBZ.
That did not make it any less popular!
DBZ - Now originally, when Akira Toriyama was doing this, he wasn't thinking past the Frieza saga at all! He figured that once Goku went Super Saiyan that was it! OH NO! The fans and publishers wouldn't let him do that! He'd created a cash cow! A venerable fortune making giant! He was pushed to continue, making the characters stronger and more insanely powerful!
Finally, at the end of the Majin Buu saga, he threw his hands up in the air and said "THAT'S IT! I WANT TO DO SOMETHING ELSE FOR CRIPES SAKE! I CAN'T TAKE IT ANYMORE!"
And so he stopped making DB altogether, but that didn't stop the money making machine as they worked with him to put together DBGT.
DBGT - Now at this point, Akira Toriyama had has it up to HERE with Dragon Ball. Other projects like COWA! or Sandland were calling for him. Something new and fresh! But the anime makers were begging him for more, and so Akira Toriyama decided to go into his roots about what originally made Dragon Ball the series it was: the DRAGON BALLS! And then it led to more fighting, and oither plot points, and it just kept going on and on and on and on, and you get the idea. Luckily, DB fever was dying down, and after 75 ill-received episodes, Akira Toriyama was finally free to pursue other work.
So basically, he did DBGT HALF-ASSED! I bet he never even did a manga, just worked with the anime folk on the TV series and movies.
That's why I prefer DB and DBZ because that's when Toriyama had his heart into it. Afterwards, it just got plain ole silly!
~Otaku-Man