My theme was Gothic/Edgar Alan Poe, and I made my key charm about his poem, The Raven. I had a metal wing charm big enough for me to add a tiny quote to, and a silver bird skull that I sanded and painted black with Humbrol enamel paint. I hung the skull up to dry, and watched the paint slide down and drip off the end of the beak, I had to keep mopping it so I didn't end up with a big solidified drip hanging off it!
However, in the end it looked quite effective, so I hung the charms off the key on a bit of silver chain and threaded some black cord through it all. It is now away on its travels, and I look forward to getting it home in a few months with other people's work hanging from it too!