I agree with Mark; I think believing in ghosts and believing in UFOs are two completely different things and aren't closely related to the same thought processes.
By and large I also agree with his assessment.
I would say that other life out there somewhere in the universe is pretty much a given. Statistically it just seems ridiculous to think otherwise. I think that other intelligent life, advanced enough to travel around space - and visit us in particular - is much more iffy, but certainly possible.
Ghosts? I'm remarkably neutral. Intellectually I'm inclined to not believe in them; spiritually I'm inclined to give them some credence. If I had to pick I'd say I don't believe in them, but it's not a "no way" kind of a no, it's more of a shrug with a "I don't really think so."
I'd take the whole thing pretty casually. If it turned out ghosts did exist the extent of my reaction would be along the lines of, "oh well, guess I was wrong." Sort of like saying, "nah, I don't think it's going to rain," only to hear thunder an hour later. No big shocker, just not really what I was expecting.
I don't really care either. I have no particular reason to assume they are either unilaterally malicious or benevolent. If they are the incarnation of people deceased, then I imagine the vast majority are pretty well balanced between mean and kind - just like living people. So I don't really care if they exist either. I mean not from a, "oh no they're going to get me" perspective nor from a "yay someone to protect me," perspective. If anything, I'd just be a bit annoyed that they might be invading my privacy.
Eh, just my thoughts,
-Kevin