Chris, you say you've "just purchased" the 606, which I understand has no pre-outs. Why not consider returning it and finding a receiver with pre-outs, you may not find it necessary if you listen to moderate levels (see John's post above) but having pre-outs will ensure you can run what you like adding an external amp if necessary. If you like Onkyo, I believe the 705 has pre's, but there are several other choices out there as well depending on your budget.

Half of communication is listening. You can't listen with your mouth.