I really like my orange spotted diamondback Goby, it has a lot of personality. Mine usually stays visible but likes to dig and make little cave homes that he sometimes stays in. When you first get one you may not like the mess it makes, but after a little while that gets much better (at least mine did).
Make sure you feed it correctly, some LFSs (like a local one I no longer visit) might tell you that these guys don't need food because they are eating bacteria off the sand; this may be true but that would be like skipping meals because you have tic-tacs. This *may* not be a problem in a larger more established tank with lots of copepods. Mine loves frozen Mysis shrimp and is doing MUCH better since I started feeding that.