Abney Park - Sleep Isabella

Abney Park is a great steampunk music group hailing from Seattle known for their fantastic costumes and creative instruments. Their site is a real treat and you can check out their myspace to hear more of their great sound.

Their bio:

Abney Park comes from an era that never was, but one that we wish had been. An era where airships waged war in the skies, and corsets and cummerbunds were proper adventuring attire. They’ve picked up their bad musical habits, scoundrelous musicians, and anachronistically hybridized instruments from dozens of locations and eras that they have visited in their travels and thrown them into one riotous dervish of a performance. Expect clockwork guitars, belly dancers, flintlock bassists, middleastern percussion, violent violin, and Tesla powered keyboards blazing in a post- apocalyptic, swashbuckling, Steampunk musical mayhem.

[Video Credit: Maxmin]

Tin Hat Trio - The Longest Night

This is a really beautiful instrumental song. The video is a little strange but not inappropriate. The large eyes on the people are a little unsettling at first but by the end of my first viewing of the video I had already grown to like them. If you want to find out more about Tin Hat Trio (who currently goes by just Tin Hat, I think) you can visit their site.
This song is also featured in a game called Triachnid that's pretty fun to play. It reminds me a tiny bit of World of Goo which is also very entertaining (in my opinion).