For the kids (or young at heart)
Snoopy
Charlie Brown/Peanuts
For the wise guy in all of us
Mad Magazine
Retro
nice comic book style Batman (similar to Amazing Spider-Man)
for Sci-Fi
Something outer space, like The Universe
could incorporate nebula, solar flares, blackhole(ball could disappear and reappear ???) quadrants, light speed, the possibilities are endless.
How about Mission to Mars (in advance of the actual mission)