With all the trailers and TV spots of Iron Man 3 being released, and all the awesome armor that has been revealed, it's only natural that people would be building those great suits out of LEGO.
There are many out there, but one of my favorites is The Hulkbuster armor by Gabe Moore. While it is LDD, and I usually don't post LDD on here, it's a great MOC, and I'm sure there are several people who could build this with real bricks.
As of this posting, the release of Iron Man 3 is less than 1 month away! Excited? I am!