I'm going to pretend I've never searched on the internet before. When I do that, I find that I have no clue what the Avengers is about. I think there's a follow-up on stuff from previous movies featuring these characters. There's Scarlett Johansson in tight pleather (check, and I do mean checked), The Thor guy (haven't seen that one yet), the Human Torch guy (haven't seen Captain America yet), the 3rd Hulk (well, I guess we really can avoid those two movies with him), Hawkeye (I saw Last of The Mohiccans), Nick Fury (star of many end-credit bonus scenes) and a lot of extra monsters left over from Wrath of The Titans (in this job market, one must not rest on their laurels). No sign of the Wasp, Ant-Man or Vision and Scarlet Witch (funny how an actress named Scarlett doesn't get to play that character) or Wonder Man, Beast (is Kelsey Grammer busy?), Spider-Man (well, there is a secret scene, but it's not much of a secret) and Spider-Woman (fingers crossed - maybe they squeezed Megan Fox in there).
As for Joss Wheddon - cross your fingers. This is really a big comeback for him after a number of mechanical sci-fi duds (Firefly, Dollhouse). If you are a fan of those, my apologies. Those DVD boxed sets don't come cheap and are not casual spending, so more power to you. You're a real fan. Seriously, the only real forseeable weakness of the Avengers movie is that it could come off very mechanical and have nothing to say beyond, "Hey, we paid-off all those end-credit scenes, didn't we?"
One last observation: while the team line-up may look like a nod to the ebb and flow of the Avengers roster over the years and the plot outline may be a nod to Stan Lee and Jack Kirby's issue #1 of the series, it reminds me of Alan Moore's League of Extraordinary Gentlemen:
Mina Murray: Black Widow
Captain Nemo: Iron Man
Doctor Jekyll/Mister Hyde: Bruce Banner/Hulk
Allan Quartermain: Captain America
Invisible Man: Hawkeye (a stretch? Maybe not...in recent years, Clint Barton had gone into hiding as Ronin after his supposed "death" - plus, they're wiseacres)
Well, we know the heroes will win in the end - because they have a Hulk...and a very relaxing luxury office, with a built-in, self-serve drinking bar.