Ok, Currently I have this HTIB in my bedroom.

http://www.sonystyle.com/webapp/wcs/...52921665065947

From my System, I plan to use the Reciever and the Subwoofer.

So Basically I am lookin for"

L + R Speakers
C Speaker
SL + SR Speakers


So Far I was thinking of this:


For L and R speakers:

Polk Audio R50 Cherry ($69.99 Each)
http://shop3.outpost.com/product/400...H:MAIN_RSLT_PG


For SL and SR speakers:

POLK AUDIO R150
Two-way bookshelf loudspeaker ($49.99 Each)
http://shop4.outpost.com/product/4965491



Center Speaker:

??????



So basically, are the speakers I posted above good? keep in Mind Im trying to go for a cheap build.
And what would be a good Center Speaker to pair it with the rest?