Good thread Grogo. I think the examples you put forward know as much as we do - what theyve read. Most of them are researchers or celebrities really. I'm convinced that there are UFO's visiting us regularly due to the weight of evidence but as to the make up of them I have no idea. As you imply everybody can't be right but that shouldnt stop any of us from continuing to question and research.
This is a well known UFO vid - STS 80 - but for anyone who hasn't seen it give it a watch because it's cool. STS 75 is great too.
http://uk.youtube.com/watch?v=QRzOF-eAw7I