I was actually wondering if the types of aliens people are drawn to creating is, at least in part, determined by what type of aliens they saw in their stories growing up--I was raised on Star Trek (no, seriously, you don't even want to get into a discussion about it with me, I'll go on for HOURS), and I didn't get into watching Star Wars until I was an adult. You mention the concept of aliens to me, and my brain jumps instantly to people wearing creative makeup, and it's only after a second that it acknowledges that, yeah, okay, there are other ways that they can look, too.