It's between new goblin and green goblin...
sandman fluctuated from being a great threat to no threat to a great threat to no threat and that was pretty bad. Infact i dont even know why he agreed to work with venom in the battle royale, his main motivation should have been getting money for his kid, spidey was never his main concern, mainly an obstacle in his way. Surely he can't be pissed with spidey because he turned him into mud, puh-lease...
Venom was no threat what so ever and probably the worst of the franchise
Ock lite just wasnt menacing enough for me, not only was he flawed as a scientist but he was also driven by artificial intelligence and reverted back to good.
New goblin would have won because he had the decency to play mind games with peter, unfortunately in two battles he lost them both pretty easily by both version of pete. He should have held his own more in the last film. I would say though that he had the best motivation for attacking spidey out of all the other villains which i feel was important.
And Mr Dafoe himself managed to do the deed. His mirror scenes are legendary, his costume sucks but his demeanor and method were still cunning. He's the only character who's BEATEN UP SPIDEY, the rest have never really phased him. He attacked MJ, his aunt, burnt a building in to tempt him, kidnapped him and tried to get him to his side, gave him an impossible choice to make on the bridge, bullied him, blew him up and beat the living **** out of him with that awesome goblin uppercut (best hit of the entire franchise). And in the face of defeat, he didn't cower like venom or go straight like ock/new goblin or sandman, he was evil through and through. Plus he inspired others to exact revenge on his behalf.