My ideal Justice League:
From what I have seen, in the minds of most creators, there are two types of super hero teams: The classic kind, who wait around for a hurricane or some bad guy to attack a city before they do anything, and "pro-active" heroes, which means in the minds of most people to be a team like the Authority, going around executing people and imposing their will upon the world. What strikes me as odd is that you almost never see a team who sits in the middle ground. A team who's goal is to build a better world as opposed to simply being a reactionary force, but aren't brightly colored tyrants/walking WMDs. Yes, they do fight evil alien overlords and save planes that are crashing, but when they're not doing that, they're not just sitting around headquarters waiting for the trouble alert to go off. Their planting crops. They're building houses. They're starting up and leading global charitable organizations. Feeding the hungry. Serving as intermediates during diplomatic meetings between world powers. Funding and sponsoring science and the arts. Setting up academic scholarships. Actually building a better world, as opposed to simply tearing down a bad one. While ultimately there would be a massive staff of people working under them in these affiliated organizations, as well as a support staff of medical technicians and ex-military to serve in times of crisis, there would be a core group who would serve as the face, as well as supplying the super power:
Clark Kent/Superman: He is the symbol of modern day super heroics, so having him on a team like this is a no brainer. It's also to resolve a problem I've had with a lot of modern depictions of him. Superman, in recent years, is often compared to Jesus, made out to be this messiah like figure. But what does he do that's particularly Christ like? He saves lives, yes, but in a very reactionary manner. He saves people in danger. He punches monsters. He isn't usually shown to be doing much to actually heal the world. Here, I'd emphasize the idea that when there's no immediate danger, he actually goers out of his way to do good instead of simply waiting for there to be trouble, as well as have him try to actually teach people a better way of life, to extend the Christ analogy a bit further. While he wouldn't be the leader of the team from an administrative standpoint, he would be from a moral standpoint. He's their rock. Their moral compass. Almost their spiritual leader.
Princess Diana/Wonder Woman: Bringing her raw power, experience in politics, and public image to the table, as well as the resources of her country.
Brice Wayne/Batman: While he'll done the cape and cowl, or even more likely just a general black outfit and mask for more covert work, if his services as a detective, his main role here is as an administrator. One of the main people bankrolling the new League, and helping them with the contacts he's built through Wayne Enterprises and the Wayne Foundation. He's also in charge of recruitment.
Oliver Queen/Green Arrow: Ollie has, by this point, left politics after a successful career as Mayor of Star City, and is using his political standing and personal wealth to head up this new Justice League along with Bruce. With the League becoming his main focus, he's left most of the crime fighting in Star to Roy, Connor, and Mia. While he serves mostly as an administrator, he still has no qualms about bowslinging again if the need arises. Or if he gets bored.
J'onn J'onzz/The Martian Manhunter: Because it's traditional, and more importantly because it makes sense. Not only because he's ridiculously powerful. Not only because his telepathy and intelligence makes him an ideal coordinator for any team. Not only because he's all around just awesome. Above all that, it's because he is the only truly international hero in the DCU. He's known the world over. He has no allegiance to any nation over any other, and has over the years done his very best to integrate himself into every culture he's come across. If anyone should be the face of a League that's truly serving in the world's best interests, it's him.
King Orin/Arthur Curry/Aquaman: Again, both because it's traditional and because it's practical. Ollie's rich, but he ain't that rich. Having the resources of the largest nation on Earth backing you up is a no brainer. I'm actually thinking that their headquarters should be in Atlantis.
Wally West/The Flash: With Jay, Bart, and now Barry all active, the twin cities are looking pretty well taken care of. This would give Wally and area to shine. And honestly, out of all the flashes, picturing Wally working on a global scale like this seems to click in my head the best.
Jason Rusch/Firestorm: An underused character that I am rather fond of. This set up would take his powers to their logical conclusion: Refertalizing farmland in war torn countries, generating usable hydrogen fuel, etc.
Alan Scott/Green Lantern: Absurdly powerful, and the only GL who's not busy with GLC business in space. Symbolically, he show's the first generation of heroes' approval of this new enterprise.
Zatanna Zatara: Putting here obscene power levels to better use that she's usually shown, doing things like healing the sick or disabled.
Hector Hall/Doctor Fate: First off, I just want to point out: Best Doctor Fate ever. I don't know how I'd bring him back, but I would. Anyway, as Zatanna is the raw mystical powerhouse of the group, she mostly uses her power in a practical way. Fate would be portrayed as coming from a more spiritual standpoint. Less of a generic fantasy wizard, more of a religious figure.
Ray Palmer/The Atom: Serves as one of the team's two scientific advisors.
John Henry Irons/Steel: The team's other scientific advisor. He was awesome when he was on the League during Morsison's run and I wanted to see him again.
Patrick "Eel" O'Brian/Plastic Man: Mostly because he's awesome, and also because I noticed that I was including pairs of two without realizing it (two rich street level vigilantes, two heroes with a royal background, etc.), and he makes a nice foil for J'onn.