If you "must" buy some new speakers to replace your Polks, and want to stay "south" of the $500 line, then I would recommend that you take a listen to the Energy RC-10s.
Also, since you mentioned that you like the NHT Classic Threes, you might keep checking to see if your dealer is going to reduce it's price. NHT is closing it's doors on March 31, so there could be some "good sales" on their remaining speakers, as most dealers will probably be dropping the line. Kind of sad to see them go, and hopefully wiil see then (NHT) on the "other side".
Also, since you mentioned that you like the NHT Classic Threes, you might keep checking to see if your dealer is going to reduce it's price. NHT is closing it's doors on March 31, so there could be some "good sales" on their remaining speakers, as most dealers will probably be dropping the line. Kind of sad to see them go, and hopefully wiil see then (NHT) on the "other side".