I made these wallpapers very simple with straightforward black or white background. I did not want to make the desktop look so cluttered (and as of the moment this is the only thing I can do with my infantile knowledge of Photoshop. :)
Update 3:
This is the Avengers Heroic Age. I feel like I'm cheating a little bit here by using Steve Rogers Cap in the place of BuckyCap.
basis:
I went with the name Avengers Prime because that is what Bendis is calling these three characters in his book. (note: though in the comics Steve Rogers no longer is Captain America)
basis for these wallpapers:
Here are the Original Avengers, the heroess that appeared in Avengers #1 circa 1963 sans Wasp and Ant-Man. (I didn't made proxy characters to complete the original five, or six if you count honorary member Rick Jones, because its a statement to Whedon that it is just not right to have these two missing in the first Avengers movie. Though I was tempted to put in that Atom from the failed Justice League America TV pilot to double for Ant-Man and Julia Robert's Tinkerbell for Wasp. :))
bases for these wallpapers:
These are the founding members of the Avengers again sans Wasp and Ant-Man. Captain America was granted retroactive founder status prior to Avengers #92 (1971).
basis:
Update 2:
New Avengers Original Team (2005) sans Echo/Ronin, Spider-Woman/Skrull Queen Veranke, Luke Cage and the Sentry.
basis: