I'm up for anything, I love all this. Not sure what I believe though..
I like the crazier ideas about human alien hybrids and space refugee dinosauroids from earth and secret nasa missions to recover mars bodies and stuff, or post roswell USA foreign policy being defined by secretly recovering a bunch of mysterious Bible age craft... Also any kind of Battlestar Galactica style space origins of human life and mythology theory gets me going...
But on the serious side... I don't really think there's aliens... But if there is aliens I think they could have come from earth.. We know life happens here, we don't know it happens anywhere else, so it's more out there to think they come from some other galaxy, isn't it....? Or no?
Also some people say they shouldn't crash so much if they can travel across space... But unless you know the total number of alien crafts flying around earth you can't workout how much they crash..... Maybe ~100% of the alien visits crash.... Maybe ~0% of the alien visits crash.... How would we know..?