As tempting as it is to simply echo the recommendation of using "a big honking rocket" as the town's center -- and DrNightmare is right, everyone does love rockets -- can I ask how large of a town you're thinking of creating?
If the town is going to be of a substantial size, developing a park (complete with fountains, flowers, statues, etc.) could be a really nice way to draw the viewer's eyes right to the center of town. For ideas, I'd recommend you do a simple internet search for the re-creation of the Beijing Olympics that a group in Hong Kong (I think it was Hong Kong, I could be mis-remembering) put together. In addition to the stadiums and arenas, they created a lovely park with a fun little fountain and lots of flowers -- something like that might be a nice anchor to your town.
If you're going for something on a smaller scale, maybe a traffic circle with a statue or fountain in the middle would suit your purposes. If you're thinking of doing more of a wintry scene, maybe an ice skating rink would work.