Top 5 DBZ characters

[anoni]

Who do you think are the strongest Dragon Ball Z characters ever and why? This is my list

5. Gohan
  Goku's son, Gohan, has shown some significant hidden power. Indeed it was him who first achieved Super Saiyan 2 and was able to defeat cell at only 50% power then. As well, when Gohan turns to mystic/ultimate Gohan at the end of the buu saga, he becomes the strongest Z-fighter at that time, even surpassing super saiyan 3 goku. The reason he is only at number 5 is simply because although he is strong, he doesn't have the fighting mentality that some of the other characters on this list have.

4. Janemba / Ultimate Buu
  Janemba is simply a small, lowly ogre that is consumed with a great evil power, on accident. This accident causes one of the strongest and most powerful entities in the Dragon Ball Z universe. Capable of totally destroying SSJ 3 goku and Vegeta as well as Pikkon, coupled with the ability to distort space at his whim, he is with out a doubt stronger than any individual z-fighter. It is only due to the fusion of Goku and Vegeta, as well as an insult, that  stops him in the end and reverts him to his natural form.
  At essentially equal strength and magnitude is ultimate buu. Ultimate buu is not kid buu, but is in fact super buu after he has absorbed ultimate Gohan. Contrary to popular belief, ultimate buu is significantly stronger than kid buu, being able to easily stop and swat away SSJ 3 goku. Even super buu in his non-ultimate form, only absorbing gotenks, was able to fend of SSJ 3 goku AND Mystic gohan at the same time, ultimate buu is a step beyond that and it is seen that he is by far the most powerful enemy in the mainstream dragon ball z universe.

3. Goku/ Omega Shenron
  So assuming that Dragon Ball GT is fact part of the DBZ universe, then Omega Shenron third strongest antagonist in the entire DBZ series. Being able to stop SSJ 4 goku and SSJ 4 vegeta as they fight him at the same time, he is seemingly invincible and his powers are almost limitless. None of the Z fighters on this list are even capable of harming goku and in fact, it is only a spirit bomb from the energy of the entire UNIVERSE that is able to finally defeat the dragon. Truly Omega shenron is a force to be reckoned with.
  The second person on this list is of course Goku, and while Omega shenron was able to essentially defeat goku head on, it is goku's strength and will that allows him to beat all odds. Goku has been almost undefeated and is definitely the strongest single Z fighter. Able to go above and beyond the limits to SSJ 4, being able to destroy Buu, Frieza, Vegeta, baby, android 17 and EVEN omega shenron. Clearly goku is the strongest fighter in the universe

2. Gogeta/Vegito
  The strongest good guy on this list is of course the fusion of Goku and Vegeta. Gogeta has shown that his powers are seemingly limitless, with super saiyan 4 gogeta being so powerful that not even Omega Shenron can stop him, or even damage him at all. SSJ4 Gogeta is so powerful that his fusion doesn't even last the normal 30 minutes, simply because of all that power. The only good entity stronger than Gogeta is vegito, at only SSJ 1 vegito was able to completely destroy ultimate buu, imagine vegito at SSJ 4? He would be with out a doubt the strongest character on this list

1. Billis/Whis
  Who is Billis you ask? He is the up-coming antagonist in the new DBZ movie "battle of the gods", the next paragraph WILL be a spoiler though, so do not read if you don't want the movie spoiled. Billis is the god of destruction, a god, not a mortal like all the other people on this list. Billis has shown "unearthly" power that is in another dimension on it's own, being able to effortlessly take out every single z-fighter with chop sticks and take out SSJ 3 goku with a single karate chop, billis is clearly a whole new concept on it's own. Even when Goku goes super saiyan god, combining the power of all the z-fighters, he is still defeated by billis while Billis is only at 70% power! Billis is the only enemy that has ever completely defeated goku, that's right, goku loses this one. Billis has a power so unbelievably powerful it is even referenced that he could destroy an entire galaxy. The only creature that is stronger than Billis is Whis, Billis's mentor, but not much is known about him, except for the fact that he is considerably stronger than Billis.

[Midnight Madness]

I'll agree with your list to some extent or another. I certainly wonder what Akira's intentions are for the series since the release of this movie, I hope to see some more transformations. Vegeta deserves to at least be even with Goku in some way or another, and Gohan could and should be capable of improving on his Ultimate form. Goten and Trunks haven't seen much of anything, at least not the current canon of Trunks.

5. Vegeta
He's not only powerful, but very cunning. His intelligence and tendency for trickery lend him a power that Goku does not utilize. It was his idea that killed Kid Buu, his idea that gave them a temporary upper hand against Omega Shenron, and his ideas kept Freiza from realizing his dreams of immortality as he struggled for the dragon balls himself. His tenacity equals that of Goku, and if the two were on an equal plane, Vegeta would gain the upper hand from his cunning rather than brute strength.

4. Gohan
Unfortunately, Super Saiyan four is non-canon, and so Ultimate Gohan still beats SSJ2 Majin Vegeta. His raw power knows near no bounds. He would be higher on the list, but due to his restraint and desire to study, he fell a little behind and weakened a bit. No less, as you mentioned, his fighting spirit is not as strong as his father's or Vegeta's. He does not enjoy fighting as much as near any of the other characters.

3. Goku
Basically, my reason for his placement is the same as yours, Anoni.

2. Gogeta/Vegito
With SSJ4 denounced as non-canon, Gogeta and Vegito get knocked down a peg. Seeing how Vegeta cannot even go SSJ3, the two forms are restricted to SSJ2. While vastly stronger than Janemba and practically any other enemy, Bills is a bit stronger. (I imagine that these two fusions could overpower a Super Saiyan God Goku by a decent bit, honestly.) Now if These fusions could take on SSJ3 or, holy crap, SS God, then not only would their power utterly destroy Bills, they might just be able to wipe out a good portion of the others like Bills and Whis. So until that can occur, I leave the fusions here.

1. Bills/Whis
Same reasons as Anoni stated.

[anoni]

GT is not necessarily non-canon. It wasn't  based on the manga, for sure, but Akira Toriyama has had very positive thoughts on the GT series, he even helped design some of the plot elements and Super Saiyan 4, so it's hard to say if GT is non-canon or not.

[Midnight Madness]

And for so long there was so much around saying that Akira himself put GT down to noncanon status. I spruced up on my research, and it appears he, indeed, said nothing about this. I'll leave my initial list alone, but if he says it is, my list will be as follows:

5. Vegeta

4. Gohan

3. Goku

2. Bills/Whis

1. Gogeta/Vegito

[Rhoryc]

5. Yamcha
4. Yamcha
3. Yamcha
2. Yamcha
1. Yamcha

I'm kidding, I just remember next to nothing about Dragonball Z