Most everyone knows my opinion on the subject but I'll try to clarify it one last time.
Batman cannot defeat Superman. That thing at the end of the last sentence is a period and it applies here with certainty.
I know that if I hit submit after typing this somebody will counter my statement with some kind of response that I will find vexing.
Every counter argument that I've ever heard about Batman defeating Superman starts off with the same word "IF".
That IF seems to be license to throw away all logic and reason however its used with unbridled enthusiasm.
"Batman can totally beat Superman if he got a piece of Kryptonite..."
"Batman is badass and will absolutely cream Superman if he got help from..."
"Batman is awesome and if he planned ahead 10 years in advance and came up with some really cool ideas he would totally whip Superman's ass!" (Which he did in some alternate reality comic published a while ago)
"Batman would be the underdog and we all root for underdogs so if Batman had all of our good vibes and well wishes he would slap Superman down so hard he'd be like all crushed and stuff!"
"Batman is the World's Greatest Detective and if he searched really hard he might find a way to give himself superpowers and then Superman better watch out!"
"If Batman pleaded with Superman to not turn him into a puddle and appealed to Superman's "I won't break your neck" philosophy...oh wait...never mind."
All things being equal Batman has nothing to fear from Superman and the reverse is quite logical as well so this Batman Vs Superman thing is a load of last night's half digested gas station burrito anyway.
Look I get why Batman fans want their favorite hero to be invincible but given the physics of the world established in the comics its just idiotic to keep having this discussion. I don't mean to be...well...mean about this but facts are facts.
The real Superman Batman fight wouldn't last long enough for the naked eye to detect given Superman's flash-like speed and there isn't anything particularly super about Batman aside from the fact that he's one tough customer and kicks the crap out of normal human being on a regular basis. That doesn't however mean much in this highly fictitious scenario that keeps spawning discussions over and over and over and over and...

IMHO