I'm no fan of Polks, JBL's, Infinities, BOSE etc., they all seem like "big box" store cheapo brands to me (no matter how much they cost, it's just over inflated prices that don't match the lower quality of other speaker's for the price, like all the great internet direct sellers these days).
I've owned budget JBL's and though they did their job for me when I was a teen (rocked out) they sounded so flat and just "blah". I also had a pair of Infinity bookshelves that while somewhat refined, were so colored, so warm and bloated in the mid-range. With Polks, I don't even think they even sound good enough in the store (yea, all speaker's sound bad in stores, but other brands at least sounded decent to me) in order for me to want to take them home and try them out. They sound hollow and tinny (though not harsh) and totally out of control with no real soundstage or depth to me. All these brands definitely sound "off" to me as well. Jmo though.
About a receiver's/amp's power: It's complicated. I don't know enough about it, but I think that most speaker's actually only need a few wpc to push them (that's why there are those small portable solid state or tube amps that only put out about 15 wpc and yet can be very expensive and push many speakers just fine) the rest are just there for the peaks in the music or if you want to push them to insanely loud levels without distortion. I think anything around 50 wpc is more than enough for a 8ohm fairly effiecient speaker (86 to 89 sensitivity). There is definitely more to a components output than just raw wpc channel anyway, like the quality of it's parts, the way it handles or channels power (the voltage it takes in from the wall), and its effeciency. There is a thread about all of this here (it deals with vintage receivers/amps but addresses all related topics) :
http://www.audiokarma.org/forums/showthread.php?t=121251