For over the counter/easy to find the Gold Class is pretty decent. Next Meguiar's has a new improved shampoo that should be worth a try. If you have a carquest (autoparts) store nearby you HAVE to try the Duragloss shampoo. It's really nice. Actually, ALL the duragloss products are awesome and carquest carries most of what they offer.
As the OP said, ONR and the Optimum shampoo are solid choices if you're into web shopping.
As the OP said, ONR and the Optimum shampoo are solid choices if you're into web shopping.