While you are thinking of buying some gear, what is your goal?
It seems like this must be an 'audio only' location based upon the receiver of choice, and the lack of proper video switcher (HDMI) and any of the features associated with that type of receiver makes me wonder what your goal and expectations are.
That said, I think Onkyo makes decent budget entry level gear, but I find their engineering quality to be lacking which leads to product that is far more prone to overheating and failure than some of the more expensive models which don't have as many bells and whistles, but have better overall build quality.
I feel about the same with many Polk products. They are good, but not where I would typically direct my money unless good was my final goal.
The 5.25" drivers are solid enough, but aren't going to be reaching into the low end which means a lot of bass will be missing within any stereo setup.
With no subwoofer out on that stereo receiver and with speakers without the bass extension, the pairing of those two doesn't seem the way to go IMO.
Onkyo:
Onkyo TX-8050 - Network Stereo Receiver | Model Information | Onkyo USA Home Theater Products
Polk:
Polk Audio - TSi Series Loudspeakers
I would probably switch up to an A/V receiver which has surround capabilities, even if you don't use it, because it will at the very least, include a dedicated subwoofer output.
Something like this perhaps, which gives you the subwoofer out, a bit more power, and a higher build quality along with the connectivity for HD audio sources (with video) if you want.
DENON US)
For speakers, the Polks may be alright when paired with a decent subwoofer. Depending on your budget, they may be all that you can get, but I would wait for some specifics on your audio expectations and some input from others on comparible (price) models to consider.
