You can't really go wrong with any of the main three comic shops on Johnson St.: Yellowjacket, Legends, and Curious. All three cater to a slightly different audience and between the three of them (and to a lesser degree Old Towne) you stand a fairly good chance of finding what you're looking for.

Aside from comics, Yellowjacket heavily promotes fantasy gaming cards (e.g. Magic), and games have... more