I stand corrected on Speed Force/Flash Force.
As far as Batman/Superman goes, as I've said, batman wins because he's prepared for such a situation, arguing over whether he did it 'Fairly" or not when using his kryptonite suit is pointless, he was prepared for a scenario and folowed through on his plans, NOT using the suit would be stupid, and thus, not Batman.
Gandalf simply would not fight all the Jedi and Sith at once, for similar reasons, even if they were all dropped in middle earth, instilled with some kind of unifying desire to kill Gandalf (Which, btw, would make them all Sith/Dark Jedi, No Jedi would have reason to kill gandalf, and so, they wouldn't try, assuming they were Jedi, the second they let their emotions/desires/whatever override their self-control, they've taken the first steps off the road f the Jedi)
But even assuming all that happened, Gandalf would find the path of least resistance, he would seperate them from afar, lead them into traps, face them one by one, scare them off, and use various tricks, the only real trouble he'd have would be with Obi-Wan, Anakin/Vader, Windu, and Yoda, even palpatine wouldn't present much trouble, as his power resides mainly in his political machinations.
This is assuming they are on middle earth, but in the Star Wars universe I think it would be even easier, there are far more places to hide and run to, lead false trails, etc.
Gandalf would win, but he wouldn't face them all at once.
As for Spiderman vs. Batman, this, again, of course, depends on the battleground, while Spiderman is highly adaptable, Batman is not, outside of Gotham his tacical strength is greatly reduced. Spiderman could swing through Gotham much as easily as he could through New York. I think the crux of this battle lies in the capability for disengagement, it certainly wouldn't be over in one encounter.
In Gotham, Batman has the capability for disengagement, he can strike when least expected, shock and awe spidey and get in some good hits, then just fade away.
Anywhere else, Spidey has the upper hand, he's much faster and much stronger than Batman is.
But again, even in Gotham, much of batman's tactical strength is depleted, because Spiderman knows he's coming. No-ne ever knows batman's coming, they've shit their pants on four seperate occasions by the time they even know he's there. Not so with Spidey, he knows when danger is imminent and when it isn't, and will have a cool head, and a good idea of the direction batman's attack will come from when it comes.
I'm honestly not sure about this one, but if it happens anywhere but Gotham, i think Spidey has the upper hand.
In terms of a neutral battleground, no buildings, etc, he still has the advantage of his agility, and batman has no cover to take advantage of.
I'm thinkin' Spidey wins this round.
Maseiken had the ball at the top of the key...