First off, FUNimation created the word "Saiyan". It is actually "Saiya-Jin". The "Jin" is japanese for "person" or "people", so it translates to "Saiya-People". Got it? Good.
Next, there are NO power levels in the Buu Saga. They were not mentioned in the series or the manga.
Another thing that I wall type about is how Gokou learned the Turtle Wave (Kamehameha) attack. If you haven't seen any early Dragon Ball episodes, scroll down a bit, this will spoil it for you. The Turtle Elder (Roshi in U.S.) went to Mount Frypan to put out the flames for the Ox King. He charged up for his Kamehameha and blew the mountain away. Goku asked if he could learn that attack, but the Elder told him it takes 50 years to master it. Goku tries it out and it succeeds, blowing up Bulma's car. Along the series he uses it more often until it is one of his most powerful attacks.
One more thing. In the Cell Saga, we all know Mr. Satan, right? A wannabe Z Fighter who was the king of wrestling or something similar. Well, He has a daughter named Videl, who Gohan marries and has Pan with. Look. His name is Satan, and if you rearrange his daughters name it spells Devil. Coincidence? I think not.
I would also like to make some comments about the various kinds of Dragon Balls. The earth kind invoke Shenlong the dragon, you get one wish, and the wish has to be within the power of the namek, Kame. If you have already wished someone back to life with those ones, you cannot wish them back again with the same Balls. The namek dragon balls are a bit different. They are larger and invoke a different Eternal Dragon, Porunga (Thanks to Zeth for some of the Namek DB info.) You get three wishes and you cannot wish someone back to life if they have died of natural causes. You can wish people back to life with the namek balls as many times as you want. There are also another set of dragon balls which are not very well known. They are the Dark/black Star dragon balls. They are scattered all throughout the universe. They invoke Super Shenlong and give one wish. they were created by Kami when he was fused with Picollo, meaning that he was at full power.
I also have to tell everyone about some double identities. In the Dragon Ball series, the 21st Tenchaki Budokai is shown. The 1st place winner is Mutenroshi, not Jackie Chun. Jackie Chun IS Mutenroshi. Near the end of the Dragon Ball Z stories, Gohan dresses up as a superhero called the Great Saiyaman. Videl (his girlfriend)(she also dresses up like the great saiya-man 2 in the movie "If goku can't do it,who can?") finds out first.
I'd also like to write about the history of DBZ. In 1985 a succesful cartoon director, Akira Toriyama began work on a humorous manga known as "Dragon Ball". It included many funny parts, such as pigs that turn into panties, perverted old men that have pet turtles, and kings named after side dishes. He was only going to draw ten strips but the gigantic enthusiasm from fanatic encoraged him to write more, going into a new story called Dragon Ball Z and eventually Dragon Ball GT. I guess he liked drawing Chibi Goku (even though Toriyama himself was not involved in any way with the creation of Dragon Ball Grand Tour), because at the beginning of Dragon Ball GT, Goku is wished back to being a kid by Lord Pilaf using the Dark Star dragon balls.
I would also like to explain Ki. You hear about ki a lot, it is a variation of the Chinese "Chi", meaning "life-force". It represents your living energy. In the DBZ stories, every major player has a decently large amount of Ki. It can be measures by your power level and if you have enough, can be used to make a Ki Blast.
Did you know that Rou Kaioushin is fused with someone? No, I'm not talking about Kaioushin, he's fused with Kibito, most people know that. But thousands of years ago, before he was sealed in the Z Sword, Rou Kaioushin looked very much like Kaioushin. Well, one day he was sitting under a tree reading a comic book, (manga), when an old witch snuck up from behind him and stole one of his earrings. These are the Potora earrings that automatically cause Fusion if both are put on the opposite ears of two different people. She put the earring on her left ear and Rou Kaioushin looked at her in horror as the two flew through the air towards each other and fused life. That's why Rou Kaioushin looks so different from Kaioushin, and that's also how he was able to do that spell to upgrade Gohan's power since he's part witch.
Did you know that Tenshinhan participates in the fight against Super Buu? Super Buu was about to do an attack that would kill Gohan, but suddenly a blast came out of nowhere and deflected Buu's attack. It was Tenshinhan's Kikohou. Of course he gets knocked out later, and dies when the Earth explodes, but hey, at least he helped unlike two other Z Fighters, ahem, Kuririn and Yamucha. Even when they were alive, they hardly even tried to help out against Majin Buu.
Did you know that Vegita actually admits that Gokou is better at fighting than him? In the episode where Gokou fights Little Buu as Super Saiya-jin 3, Vegita is off to the side watching and contemplaiting Gokou's actions and powers throughout the years. Finally he figures out that why Gokou is so strong. He fights not just for his personal goal, but for the safety of others, as well as personal enjoyment. He doesn't fight just to win, just to have a good time. He remembers all the times Gokou surpassed him and finally his speech ends with, "Gokou, you truly are Earth's Number 1 fighter!"(but that's wrong,when vegeta uses brute ray and they fuse to make yours truly,gogeta,he has a double power which is like 3 vegeta s or two gokus so he's more powerful!!).
Did you know that there's a pretty funny episode near the end of Z where Buruma holds a party for everyone, even Dende is invited. Everyone has a good time, even Vegita, who after getting drooled on by Buu, actually smiles and gives him a sandwich. Everyone's there except of course, yep, Gokou. He's off protecting some terrydactyl eggs. But eventually he shows up. At the very end of another late Z episode, there's a cute bit where Gokou is splashing around with Goten and Trunks in his water basin. Eventually it gets aggressive and Gokou holds the kid's heads under-water, but then they hop out and do fusion naked, becoming a nude Gotenks. Gotenks jumps in and tries to overcome Gokou, but Gokou turns into Super Saiya-jin 2 and the water basin explodes leaving a naked Gokou happily staring down at his attacker. Buruma and Ch-chi rush forward to cover up their little warrior..er...warriors.
Nappa actually did have hair once! It was only shown in the Bardock TV Special. Here is the pic.
Here are two pictures of Akira Toriyama(this guy rocks!).