The only cable you may want to purchase would be an optical cable if your
Receiver supports it. They're spendy, about $25 for a 3ft cable at Radio
Shack. Turtle Beach sells a 13 foot Optical Cable for $24.95 in the
Accessories page. 

The AT has a digital out which allows you to bypass the digital to analog 
converter (DAC) in the unit and directly output the digital stream to your 
Receiver.  This allows you to keep the signal in digital form all the way 
from your PC to the Receiver.

However, to be able to use the optical cable, your Receiver needs to have 
an available digital optical input.  If not, just use the standard RCA cables
provided with the AT and allow it to do the digital to analog conversion.
However, the quality of Digital is superior to the Analog, so utilize the
optical output if at all possible.

If you do go the optical cable route, you may also hook up the RCA cables to
your Receiver.  This will allow you to listen to Internet radio stations which
are not broadcasting at the standard frequencies allowed by optical
connections. If you do not do this, an Internet radio station broadcasting at
say, 22kHz will look as though it's playing but you will not hear it if you 
don't have the RCA cables connected.

_______________________________________________________________________________