This will be a quick post, don't have much time right now.
Ascend Acoustic: CMT 370SE x 3 for the fronts CBM 170SE(pair) x 2 for the rears. Around $1330 shipped.
Sierra-1 x 3 for fronts, CBM170SE (pair) x 2 rears. $1810
http
/www.ascendacoustics.com/
SVS: Prime Tower x2 (L/R), Prime center, Prime Satellites x 4. $1750 (Could get another Tower for the center if you want for an additional charge)
Prime Bookshelf Surround package + 2 Prime Sats. $1250
http/www.svsound.com/pages/speakers
Hsu Research: 7.0 speaker package $1230
http
/www.hsuresearch.com/
EMP Tek: R55Ti x 2 (L/R), R56Ci center, R5Bi(pair) x 2 rears. $1540 shipping may or may not be free.
R5Bi(pair) x 3, R56Ci center. $1070
http
/emptek.com/
This is just off the top of my head. Probably the best option is the Sierra/170SE package, with the best value for the dollar being the 370SE/170SE or the bookshelf EMP Tek package though all of them are solid, mid range choices.
Also, I listed some with towers and some with just bookshelves. Towers do have advantages over bookshelves, but in most of these cases here, they are probably minor and not necessarily worth the extra money over their bookshelf counterparts.
I'll also point out the the Polk Sub isn't a particularly good one and will be the weakest link for any choice here. I'd suggest replacing it too, maybe not now but at some point. Some very good choices would be:
Rythmik LV12R @ $569 and will receive a discount when purchased with ascend speakers,
SVS PB-1000 @ $499 can be discounted with SVS speakers,
Hsu VTF-2 MK4 @$530 discounted with Hsu speakers. These are a clearly a couple of steps ahead of the PSW505 and when paired with some of the more modest suggestions, will come in under the $2000 top end. But then again, if you are happy with what you have then there isn't a need to upgrade.