Artwork in the form of canvases or framed posters is a great idea, alternatively there are some lovely Steampunk wall clocks available. You can find Steampunk designs on throw pillows or you can get some gorgeous ornaments that have a Steampunk flavor to them.
Steampunk - this page talks about Steampunk, but also discusses adding Steampunk to your home.
Steampunk Clocks - as it says this page is all about different Steampunk clocks so if you like the idea of one of these wall clocks, but the one's I've featured above don't quite grab your attention then you might want to check a few more out.
Steampunk Dolls - Now this is also self explanatory and features dolls with a Steampunk element - some people like to display dolls in their home and other people don't.
Steampunk Gifts - this page features a few things which would be nice to have in your home including some Steampunk weaponry like vaporizers and the like which look great on display and also double as a great conversation starter when you're entertaining.