As default mcGateway sends out beacons from the modules on mcThings/beacon so if you subscribe to mcThings/beacon/# then you will receive those messages.
But I would guess that you gonna publish your own messages maybe like this mcThings/Temperature/Kitchen and mcThings/Temperature/Bedroom so then it would be better to subscribe to mcThings/# to fetch them all. Or just # to get all messages, depends on the number of messages arrives at the broker you use.
Please tell me what you want to accomplish and then I could post a better answer based on your needs.