Help me pick speakers for this receiver Onkyo HT-RC160

http://www.amazon.com/gp/product/B0028AD7BE/ref=oh_details_o09_s00_i00

I got this receiver 3 years ago as a Christmas present. I have somewhat figured it out, used Audyssey to set up my speakers, but now I'm at a point where I want to upgrade my speakers, and I'm wondering what this receiver is capable of. As you can see it is only 80 watts per channel. I'm interested in either just 2 tower speakers, or possibly a 5.1 surround setup. But for the sake of simplicity, please let me know what pair of tower speakers would work nicely with this receiver. Trying to stay under $5-600 for the pair.

Also since its 80W per channel, if I'm only using 2 channels, that seems like a waste. Is there anyway to put those other watts to use and power some better speakers? Would that be "bridging" or something?

Currently have these Sony's, and I think they are barely adequate for even watching tv. Dying to upgrade.
http://www.amazon.com/Sony-SS-F6000-Floorstanding-4-Way-Speakers/dp/B000OG4E20/ref=sr_1_1?s=electronics&ie=UTF8&qid=1360548845&sr=1-1&keywords=sony+ssf6000


Just wondering what speaker would be able to take advantage of this receiver and sound great loud and clear.

Thx postrokfan. Looks like Amazon has the infinity primus P363 for $168 each:
http://www.amazon.com/Infinity-Primus-P363-Three-way-Floorstanding/dp/B0046A8R3M/ref=sr_1_3?s=electronics&ie=UTF8&qid=1360587318&sr=1-3&keywords=infinity+primus
Can't help but notice how almost identical these look to my Sony's posted above. Two 6.5's etc. You really think these will be night and day better than my Sony's? Should I look for a set with bigger woofers? The Sony's produce barely any bass, and I'm wondering if my 80 watts per channel is not enough to make any speakers sound good. ou think my sonys or onkyo receiver are more likely to blame? Also do I have the right ohms? I will add a powered sub later, whenever I'm not in an apartment with neighbors etc, so just looking for decent towers that will work well with my 80w per channel. Or if I should just dump this receiver too and get a higher power unit. Ugh.

Pretty sure I'm going with the Pioneer SC-1222-K receiver to have a good amount of power. With this upgraded AVR what do you think about these 3 speaker package options. Already have 2 old jbl bookshelves that will serve as my rear surrounds, and not interested in a sub right now. So only looking for fronts and center speaker.

Infinity Primus
P163BK only $260 pair on amazon
PC351 center channel. $279

JBL
L830 fronts $500
LC2 center $290

PSB
B6 fronts $550
C5 center $400

I hear good things about all of them. The sc-1222-k is 4 ohm certified. These are the 3 options I have researched so far. Any advice is always appreciated!