I'd press charges - if the case goes on record, the pawn shop is alerted to an interest by the authorities, and will (hopefully) be more attentive as to the source of their goods.

For the thief, this may be the wake-up call they need to stop stealing. True, it may make them more determined not to get caught, but at least this puts a kink in the pattern. At a minimum, it alerts their friends/accomplices that people DO press charges, and there may be a consequence.