Long answer: Skeptic. I'd like to believe in an afterlife, but as my life says, if a ghost were to punch me in the face, I'd think it's my imagination. Also, I see nothing that makes any religion more or less real than any other, so I choose not to follow any. However, I think highly of Buddhist philosophies, mostly because going against many have real-life consequences, rather than angering some invisible higher power.
I also consider my Trinity to be Thor (I still claim praying to him when I was younger and Catholic cured my chronic nightmares and insomnia. Gotta go with the results!), Murphy (whose laws I've see way too often), and William Blake.
Short answer that I give most people: Atheist or skeptic (Usually atheist because I love the reactions!).