That's a tough question. An atom doesn't actually look like anything- they're so small that a light wave just sloshes over them without usually changing enough to see. Even if the atom absorbs the light (as sometimes happens) that doesn't give you any sort of picture. Light can't really resolve things much smaller than ~0.1 micron, and atoms are 1000 times smaller than that.
So let's take your question another way. Using the sorts of measurements that we can actually do on atoms, what sort of state do we think they're in? Are they like the pictures you often see of massive little balls (nuclei) with tiny dots (electrons) whizzing around like little planets? They aren't.
There's a lot to say about what they are, but maybe this will help you get started. For some nice movies to help picture this better, you could visit http://www.falstad.com/qmatom/
There are compact, heavy nuclei in the middle. There are lightweight electrons around them. However, the electrons' states cannot be described as positions and velocities. Instead they are spread-out, cloud-like things. At every moment they have a fuzzy range of positions, and a fuzzy range of velocities. They're much more like waves (think of patterns on the surface of a pond) than like moving dots.
(published on 06/13/11)