Best speakers under $500? Fire away!

If you can arrange for an in home trial- you can get a better idea of compatibility with your amp, room, music and "ear". A lot of stores will loan out stuff for a week or so, especially if you put it on a card and refund on return. Worst case arrange to pick up their demos on Saturday (with a card charge & return/refund plan), play with them for a day or two (specialty stores are often closed on Monday, or have minimal traffic). If you can, try to get two or three pairs of your favorites at the same time to compare. 

with the dentons and wharfedale in general, you would not believe the quality of the cabinet, the grill,  and binding posts you get for the money.  
In terms of sonics, they are on the warm side, mellow, laid back, very smooth and zero harshness highs, easy to listen to.  I have them powered by a marantz integrated that is also warm and laid back, and I do not feel like it is a good combination.
They are not monsters of details and air, nor do they fill the room, but that is compared to my totem hawks. They image ok, soundstage ok.
In my room, they are good for low to moderate volume listening, toed-in on axis 8ft away.  If the 3020 sounds like the NAD integrated I once had, dynamic, punch in the lows and the highs, then it could very well be a good match.
The dentons need power, more than my totem hawks.

Yes, all LS 3/5a style speakers need clean power amp, do not try ady warm signature amp like Marantz, not saying it's not working, just not the best

Been listening to the Q Acoustics 3020's for a day or so now.  They are warmer and more refined than the Klipsch RB-51's.  Top end is extremely accurate, mids are nice and bass is tight and precise.  I have them 7" from the wall which seems to be pretty good.  

Next up will probably be the Wharfedale Dentons.  

My NAD 3020 is having no problems whatsoever driving the less sensitive Q's.  Very impressed with this little gem of an amp.  

Your NAD 3020 can drive any reasonable bookshelf speakers easily , you don't have to be worry about the speaker's rated sensitivity .
Wharfedale and Q Aaoustics are fine for its cost but not great speakers .not bad sound at all but certainly  not overwhelming.