Right now, I think robots are where it's at. And yes, I'm biased. Robots and space, because with home rocket kits and Lego Mindstorm sets, people can get involved. I was raised on Transformers and GoBots, so I can't imagine what kids who are building real robots are dreaming about.
No matter how much kids beg to be treated like adults, nobody likes to let go of their childhood. You wish for it and dream of it and the second you have it, you wonder what you've done. You wonder what it is you've become.