Check out this chart of Iron Man's armor evolution

We're going to need a bigger boat...
(Click to embiggen)

It's a pretty handy chart if you're not wholly familiar with Iron Man's armors. Kate Willaert from HalloweenCostumes.com did a fine job creating it, so a tip of the Nerd-Thing hat to her. The only ones not listed are the one-offs that he wore once or twice, the specialty armors like the stealth, space, and aquatic, and the armors he created as revisions and overhauls of existing armors. Oh, and the armor the teenage Tony Stark wore in the mid-90s, but I think we'd all rather forget that that ever happened. Yeah.

My favorite of the bunch is and always will be the Silver Centurion. It's funny, I've never read an issue from when Tony was wearing the thing (which will be rectified one day soon), but I just totally dig it. The Silver Centurion just looks so different and cool! I was surprised by the five longest running armors; I was sure Extremis had all of them beat. Glad I was wrong.

Now having said all of that, it's unpopular opinion time: I don't like the movie armors, with the exception of the Mark I. I don't know, they just look too much alike with hardly any real variation. I think the only difference between the main armors in the first two Iron Man movies was the shape of the unibeam/arc reactor piece. The newest armor from the upcoming third movie is mostly in the same boat. It looks like all they did there was swap the red-gold palette, and changed the shoulder guards, the boots, and made minor changes to the helmet and torso.

Hat tip to Geekologie for the picture.