Goku vs Nappa: You sure? Nappa never touched goku and went down with 2 punches.
Goku vs Cpt. Ginyu: Goku won easily, Cpt. ginyu thought he was a super saiyan and exchanged bodies before he got killed.
Goku vs Pikon: Id say goku was stronger when he went SS 2 on pikon.
Freiza vs goku: Talk about bias dude, lets talk vegeta, he went down with one finger of freizas. Goku beat freiza and became a super saiyan. Freiza destroyed the planet because he thought he would lose, also goku survived and trained in yardrak, and also become much stronger than Trunks was when he beat freiza.
Goku vs Cell: What can you expect? Cell was stonger than every single fighter there(including gohan) if it wasnt for vegetas big bang gohan would have been destroyed.
2008 end of year predictions:
PS3: 22M
360: 25M
wii: 40M