Hawkeye's got that Ultimate look to him, and Iron Man is sporting the Mark VII. I'd be disappointed if we don't see a Mark VIII in The Avengers, just because that's how he rolls. Hopefully, we get a Mark IX and a Mark X in Iron Man 3. Black Widow is using her stingers, so that's a good sign. Also, I love seeing a shouting Captain America. Intense Cap is the best Cap.
Marvel, what we really need now is something in 1920x1080 wallpaper size. Thanks muchly.
Samuel L. Jackson as Nick Fury is a perfect fit, mainly because the Ult version of Nick was based off him. I'm sure you knew that and didn't need to be reminded, but typing words on this thing is free anyway so let me have my fun.
The image shows him keeping tabs on his superhumans via a SHIELD interface that looks suspiciously like the one Tony Stark uses. Hmmm... something could be afoot. Moreover, if you give the files and design elements a nice hard look, you'll notice a file that says "CHARLIE09" and that file is locked. Who could that be? How many Charlies are out there in the Avengers mythos?
Finally, we've got the god of mischief, Loki. Hiddleston did such a bang up job in the Thor movie, it's hard to imagine anyone else as Loki! He's a perfect fit for this, hands down. Everything looks great. I love the costume, I really do. It's more future tech than Norse (i.e. more rubbery textures rather than Viking animal hyde) but I am enjoying it. I hope he gets to keep the helmet for his entire stint as the devious one!