Steampunk is kind of silly. It's hard not to smirk at someone in 19th century garb, complete with top hat and coattails, who also has goggles and a raygun. But the silliness of steampunk is part of the charm. And just because something is silly, doesn't mean it can't be great.
Case in point: Royden Lepp's wonderful graphic novel RUST.
Rust is an imaginative adventure story set in the prairie lands of an unknown time. It has all the hallmarks of steampunk: goggles, jet packs, big clunky robots with lots of gears. It's even colored in shades of sepia (it doesn't get more steampunky than that!). But it's also touching, funny, and intriguing. The graphic novel is drawn in an engaging, playful style that's reminiscent of both Calvin and Hobbs and Manga. The story centers around a mysterious boy with a jet pack who crash lands on a struggling family's farm. Then the big robots show up...
There are currently two books published in what is planned to be a four-book series:
Check them out. They're kind of silly. But they're still great.