Best speakers under $500? Fire away!

Not sure what speaker characteristics are most important to you, but an excellent all-arounder is the Silverline Minuet Supreme Plus.  It's not a hard speaker to drive and should be in your price range used.  Best of luck. 

I believe the Wharfdale 10.2 is on sale by Music Direct. Better than the 10.1s for your size room.  I believe easier to drive than the Elac B6, which is otherwise a easy recommendation at it's price.

Again, once one gets past the speaker/amplifier synergy issues, the choice of speaker is so subjective I hesitate to recommend a specific pair.

Good luck in your search.

"tls49... going to listen at higher levels and will see how many lights illuminate.  I was at only 10 o'clock volume the other night and 4 of the lights lit up."

If you listen at levels that cause that 5th light to illuminate frequently, then that is extremely close to the maximum capability of your system. It has nothing to do with the position of the volume control. Also, I'm thinking you should only consider speakers with a sensitivity above 90db unless you plan to replace the 3020 with a higher wattage amp. A 92db speaker would require 40 watts to have the same capability as your Klipsch/3020 combo, a 89db speaker would require 80 watts, and a 86db speaker would require 160 watts. Every 3db is a double or a half of power depending on the direction you're going.

Used B&W 685 is a great option too,one of the best B&W ever made ; spacious soundstage ,extremely detailed and great dynamics. 

Elac UB5.  Slam dunk.