[Sonnie]

Personally with those Polks I see no reason for you to even be considering a separate amp. The Onkyo will make those speakers do just as much as any amp will make them do. You can buy one... and if you do, take the time to listen to the receiver with the speakers and then the receiver/amp combo. You'll probably not know the difference. Those Polks are not difficult to drive and will be very happy with the Onkyo on its on.

Another thumbs up for the SVS subs. I would take the money you were going to spend on that extra amp and apply it to your sub budget. You'll be much happier in the end.

Nothing special is needed for cables. Monoprice.com and TendonUSA.com should supply you with all you'll need, which will most likely be HDMI and speaker cables.