I am open-minded but definitely skeptical as well. I have had some insane unexplainable experiences, but I don't know if ghosts would be the first thing I would jump to. There is also the fact that if you already believe something, you are going to interpret whatever you see in the way that you want. Reality is also based completely on perception... so if someone believes in ghosts... they are real to that person, whether they actually exist or not. I digress. I was trying to get at the fact that I am very skeptical of my own experiences, because I am aware how cool I think it would be if those experiences were due to "other worldly" beings haha.
On the science side of things, on a very basic level I know that like everything, brainwaves are a form of energy and energy is never created nor destroyed. So the idea that someone's consciousness could uptake a different form is not far-fetched for me, however I don't know that I believe people hang out in their human form because of unfinished business. I don't know if I would say I believe in reincarnation, either, but merely that your consciousness disperses into the world, so that you are not collectively "you" anymore, but still your consciousness is out there to be used in any other energetic process in the world... hell, in the universe!
Totally unscientifically, I do think if a "spirit" were to take on a ghost-like form, I feel that it would have to take extreme will/intention on the part of the deceased because working from the model of entropy, it seems it would take quite a lot of work to keep brain waves together once your brain is turned off. So I think that would only happen if the deceased did want to communicate with someone. I don't know if it would be possible to communicate, or if that even makes sense lol, but that's just what I think... and like I said, I have had many unexplainable experiences which turned me from a non-believer into a hard skeptic of spiritual/magical forms of life.