What are the best locations to install an XM radio in an 1999 Toyota Camry?

I have a Roady XT. I cut a circular black of wood that looks about the size of half a soda can. I screwed the mount into that and I keep it in a cupholder. I can easily move it from car to car that way. To run the antenna, I ran it through the back seat (which opens) into the trunk and then onto the trunk lid. vbd