The League of Extraordinary Gentlemen is a classic example. I don't understand why people hate that movie so much, I loved it! It was fun, it had colorful characters and awesome steampunk tech... What more can a girl ask for?
I totaly didn't register Wild Wild West as a steampunk movie when I first watched it, I was too focused on the wild west theme, but looking back now it was steampunk as fuck! The giant spider, Kevin Cleins gadgets, pretty much all of it. Definitvely worth a re watch.
The Three Musketeers? Really? When that movie came out I remember thinking "meh, just another musketeer movie that probably can't come close to The Man in the Iron Mask", but after seeing this trailer I'm downloading it as we speak.
These are all great suggestions, keep them coming