The only reason we use dish soap at work is if a pet gets something oily in their fur that isn't coming out. Especially the trash the Hartz advertises as flea prevention. We use a bit of Dawn, and follow it with a conditioner to avoid drying them out.

Jasper's skin and coat are both resilient and basically odorless, so I just find a nice oatmeal/tea tree oil shampoo...there are several brands I have been pleased with. If he gets REALLY stinky for some reason (Last time he rolled in a dead bird...where do they get these ideas? ) I mix in some baking soda.