In-wall speakers & Subwoofer

[jc480]

After mulling over my home theatre options, I've decided to go with an in-wall speakers/center & subwoofer setup.

My choices are...

(3) sets - RC80i 10.75" in-ceiling Polk speakers
http://www.polkaudio.com/homeaudio/p...g/hidden/rc80i

(1) subwoofer - CSW200 10" in-wall Polk Subwoofer
http://www.polkaudio.com/homeaudio/p.../hidden/csw200
*site indicates a 500-watt amp...do I really need this if I purchase a decent 7.1 receiver?

(1) center - LCi-C in-wall Polk Centerchannel
http://www.polkaudio.com/homeaudio/p...r/hidden/lci-c

(1) Receiver - Onkyo 700+ series or equivalent receiver

(1) 500-watt amp - DO I NEED THIS?

(1) BDP-S550P Sony Blu-Ray Player

(1) Sony KDL-52XBR6 -OR- Sony KDL-52W4100 (depending on sales post x-mas...still trying to decide if the XBR6 is worth the premium)

The room this is going in is as follows...
Height: 11 feet
Depth: 20 feet
Width: 12 feet
Shaped like a rectangle with the TV going in the center of a 12-foot wall...ceiling speakers will be mounted (2) front of room, (2) rear of room & (2) center of room...center channel will be mounted underneath TV and subwoofer in lower right corner of TV wall

My questions are...
Is Polk a suitable brand for my purposes? I realize I am paying more for the convenience of in-wall speakers...are my choices good or is there a better value out there? I'm worried about matching which is why I stuck with Polk across the board...they also seem to have a nice selection along with good quality installation guides, etc

Thoughts on the TV? I like the Sony brand and I was pleased with the picture when comparing to others at BestBuy...the XBR6 seemed a bit better but it was hard for me to quantity vs the W4100

Do I need the amp for the subwoofer or will that receiver be fine? I believe this subwoofer powers down when not in use.

This is my first HT. I am not an audiophile but I can tell crap sound from good sound...although I probably cannot differentiate the degrees of good sound like an experienced audiophile.

Any input would be greatly appreciated.