Having a low budget, this stuff seemed relatively no brainer and well-liked by the searches I've done on the forum, but I thought I'd ask you experts anyway. Anything about this you would change/upgrade? Mainly concerned about receiver being good enough to the speakers, any worthwhile speaker upgrades, etc.
Front/Surround: 4x Polk Tsi500
Center: Polk CS20
Sub: Polk PSW10 (Placeholder until I get a bigger place)
Receiver: Onkyo TX-SR707
Right now it will be for a relatively small room (the combined living/dining area of my 1br apartment) about 14x25ft. I see most people use different speakers for surround speakers, is this just a pricing issue? Obviously I don't have all the money in the world, but since a pair of Tsi500s only cost a couple hundred more than a lower model speaker, I figure I can keep them for the surround too.
I know I shouldn't be worried about the CS20, but is there anything better I should consider? Voice quality is very important to me.