Interesting read Mason. I've never believed in ghosts either, but I'm not so stuck in my beliefs that I'd dismiss solid evidence. Especially if I saw something like that with my own eyes and heard it with my own ears like you did!
I'm an analytical type of guy, always thinking. If that happened to me, I'd be compelled to think it through too - to try and rationalize the experience and see if there was a better explanation for "what really happened".
If I couldn't come up with any sort of alternative theory, then I'd have to move my skeptic-o-meter from "highly unlikely" to "further observation required".
You see so many show on the tube that tell stories of people encountering ghosts. Sometimes it seems plausible, but they never provide any proof beyond the story itself.
Or you go to a tourist attraction, and the employees will tell you that it's haunted and relay some of the experiences that some of them have had with the ghost(s). I've usually dimissed it as "going with the territory" - part of the supposed thrill of the attraction.
I'd be interested to read a follow-up on your thoughts.