I offcourse choose Buu,i mean in dbz he is the far the strongest and is quit indestructble.
Many think goku is equal to Kid buu as ssj3,maybye at 100% he is equal for a few kicks and such, but gokus energi drains fast ast ssj3 and Buu isnt wasting any energi in transforming.
And why do so many people take weird comperings,like:
Buu vs Frieza or Majin Vegeta vs Brolly?
Now i will make my point
In frieza saga Frieza is far the strongest untill Goku transforms into a ssj after wittnessing his best friends death and becomes the strongest in the universe (But he isnt really the strongest in the universe,because Dabura and Babidi also exist then but back to the story) after that point Frieza never surpasses Goku again.
And comparing Frieza to Buu is like comparing Mr Satan with Vegeta.
And brolly vs majin vegeta,in the first movie Brolly appears we can all se that Gohan hasnt learn how to become a ssj 2,then the timelime would have to be just before the Cell tournement,and as we all can see Brolly is far superior to them all. But that was then,you all know how much both goku and vegeta improves to Buu saga were Vegeta turns Majin. There wouldnt even be an equal match,vegeta could beat Brolly with one hand behind his back,dont get me wrong..iam a big fan of brolly:>
And the thing in gt,were hell and earth connects and goku gets trapped in hell and fight cell and frieza. Indead they have both improved alot but goku is far superior and kills them. Which everyone by now most know. If you die again after you have died you sease to exist in this realm. But sure it would be a great loss indead if cell and frieza just totally seased to exist.
And i guess you mean Spirit Bomb when you write sp,it´s used only one time in GT if i remember correclty. After Evil Shenlong had defeated all members in Earth special forces and is sure of his victory Goku appears from a large creater with a spirit bomb who has energi from the whole universe. He knows the blast would kill him so he tries to escape but meets his doom.
And 2 more points, Super Buu /Mystic Gohan/Piccolo/Gotens/Trunks/ is Very powerful indead far the most powerful form of Buu. But he could easily been defeated by Vegetto. Made som research in Vegettos power, seems Superbuu´s power is about 700 million and Vegetto as ssj was 1.4 billion,and to make an powerful example the one to reach that level of power is Goku when he turns himself into a ssj4,and may i remind you that both vegeta and goku can turn ssj2 so vegetto could have boosted up his power alot more.
And i have seened questions like if Chibi trunks and chibi gotens is fused together and can transform into a ssj3 as gotenks,wouldnt that mean they can turn ssj when they arent fused? Sure they could,they have the knowledge but now the power to become a ssj3,they are to weak for that. And in gt the knowledge must have been lost or the idea for them to ever become a ssj3.
Cant come upp with any more points for now,so that´s it.