SORRY I POSTED ON GENERAL QUESTIONS JUST GETTING A HANG OF THE SITE!!!
The question that i am posting today was asked to me by a friend of mine and in my heart of hearts i could not come up with a clear cut answer, so now i am looking to you for the answer " Who would win in a battle between the Justice League and the X-Men?"
Cliffy you are a/an &@)&@#()&#(
Depends on which incarnation of the teams and which versions of the characters show up.
If you exclude the higher-level telepaths, then Flash, Superman, Green Lantern, Wonder Woman, Martian Manhunter, or a prepared Batman could take out the rest single-handedly. OTOH, most of the JL could be quickly controlled or incapacitated by Professor X or Emma Frost.
So really, it all comes down to this: Can the Flash take out the psychics before they work their mojo, and if not, can Wonder Woman and the Martian Manhunter take out or free their mind-controlled comrades?
We did this awhile back. Here’s the rather long thread.
Just a note: The SDMB Powers-That-Be tend to frown upon reviving old threads, although I get confused between the differences between the differing forum rules on this subject. Still, it is a good reference that lays the groundwork for discussing the subject here.
Oh, and to answer the question:
Most incarnations of the Justice League will beat most incarnations of the X-Men. The Martian Manhunter counters Professor X, and Superman / Flash / Wonder Woman can pretty easily handle any fight.
The true comic geeks can come out and find specific X-Men lineups that could beat specific JL lineups, but IMNSHO they would be the exception, not the rule.
What Doddsie said. Both times.
A better question might be “Has there ever been a configuration of the X-Men which could have defeated the configuration of the JLA being published at the same time?”
Phrased that way (and assuming we disallow times when the JLA was disbanded, which happens every few years), I can name one. The late 80s-early 90s X-Men–Storm, Wolverine, Colossus, Psylocke, Dazzler, Havok, Longshot, and Rogue–would have owned the roughly contemporeaneous Detroit-era Justice League.
As much as we kicked this battle around in the prior thread, I’ve got to give it to the JLA.
Sure, there are some wrinkles. Any team with a Phoenix on it is going to give them some fits. Rogues powers would make for some fun. Longshots uncontrolled luck powers would give him an edge versus the entire league.
Overall though, the JLA just has too durn many godlike heroes for the mopey mutants to handle.
Then again, you could just go all comic booky and have the series wind up in a tie as they join together to fight whatever cosmic bottom burp brought them together in the fist place. 
I actually get very frustrated reading The Flash, because outside of the way he was handled in Mark Waid’s Kingdom Come, its hard to see how anyone could get the better of him, psychic or not.
Good idea, but JL Detroit was pre-crisis and ended its run in 1985. Their contemporaries would have roughly been: Storm (in punk mode), Wolvervine, Colossus, Nightcrawler, Shadowcat, Rogue
Thereabouts, yeah. By '87, it was JLI, with Batman, Dr. Fate, Guy Gardner, Martian Manhunter, and Captain Marvel on the team. Arguably, one of the most potent configurations of the League ever.
I’ll have to respectfully disagree. You are leaving out two very important members who, together, removed the potency of the one’s you listed by a degree greater than any villian they ever faced. Plus, you listed Guy, who actually helped the other two drag down the Martian, the Bat, the Doctor and the Big Red Cheese.
Booster and Beetle weren’t hindrances in the individual-mission sense, merely in the overall organizational sense. I also left out Black Canary and Mister Miracle, too.
Didn’t the X-Men once get their collective asses handed to them singlehandedly by Spiderman? And how many members of the Justice League, in just about any configuration, could easily take Spiderman out in a one-on-one fight?
That happened during Secret Wars, where the lineup was Cyclops, Storm, Wolverine, Nightcrawler, Colossus, Rogue, and Professor Xavier. Granted, he did have the advantage of surprise (and it wasn’t so much a pitched fight as Spidey busting in, slapping them around, and darting out) but still pretty embarrassing considering Xavier is a telepath and should have known he was coming. But the X-Men were pretty poorly written during that miniseries.
I think probably the most powerful X-Men roster ever was around Uncanny X-Men #200, featuring Rogue, Nightcrawler, Colossus, Kitty, Phoenix II (Rachel Summers), Magneto, Wolverine, and the powerless Storm. This was the team that took on the Beyonder and lived to tell about it.
It was in an issue of the first Secret Wars series. He bounced in, knocked them around a bit (and put to rest any notion that either Nightcrawler or Wolverine could beat him an in agility contest). The incident was triggered by his eavesdropping on their plans to abandon the “hero” side of the secret war and join forces with Magneto. Spidey was about to spill the beans to Reed Richards, but Professor X (who’d been briefly stunned in the skirmish) recovered and wiped his memory.
Oddly, about five issues later, Spidey is tangling with Titania and casually trashes her, commenting “With a little room to maneuver, no-one can lay a hand on me. Not the Absorbing Man [who had swung and missed at Spidey a few pages earlier], not the X-Men, and not you.” The inconstancy is not explained.
What’s wrong with the Flash? In that horrible The Kingdom follow-up, Magog could see that The Flash excited the ions before him, telegraphing his arrival. The Flash is super-powerful and super-versatile. Given his power level, he should be able to take on most of the X-Men singlehandedly.
The problem with these debates is that superheroes like the Flash should be nearly unbeatable but they are never written that way. If Wally West used his powers to their full extent, then villains like Boomerang or Captain Cold would never give him any problems – he could beat them to a pulp before the signals from their brains reached their hands. But of course he doesn’t utilize his powers that effectively, neither does Superman, or Wonder Woman, or most any other superhero. In an actual battle, Wally’d probably coldcock Shadowcat or somebody, and then stand there and make a quip while Psylocke mindwiped him.
For the record, I doubt any incarnation of the X-Men could beat the JLA. The DC heroes are just too overpowered. But I think the Uncanny X-Men #200 team pre-Mutant Massacre could give them a hell of a lot of trouble. The Avengers, once again depending on the lineup, are a much fairer fight. They’re definitely Marvel Earth’s Mightiest Heroes, and include such heavy-hitters as Thor, Sentry, Pulsar, Wonder Man, and Sersi. Check out the JLAvengers miniseries for this.
The X-men team that fought Horde in an X-men annual was pretty good, too. Storm (no powers), Wolverine, Longshot, Dazzler, Rogue, Havok, Captain Britain, Megan, Psylocke…who did I miss? 
Mississippienne has answered this for me.
I don’t disagree that some Avengers teams would make it a good fight with the JLA. However, I do disagree that the Avengers are the Earth’s mightiest heroes, despite the billing. Dr. Strange. Namor. The Hulk. The Silver Surfer. This is Earth’s mightiest superteam.
It would be, if they weren’t bickering with one another and if the Surfer would have anything to do with them.