Full Range under $5k-ish

A plethora of recommendations, as usual! Let me add another: ATC SCM 40. Should be around 4k; if not, go for a recent pair of used 40 or 50 in your price range. Stunning dynamics, imaging, and detail (not harsh). Need power, but you already have that.

You can get Focals for your price range.  Not their top of the line stuff, which is out of reach for most people.  ATC seems to be with-in your budget.  If I was spending 5k on speakers I would audition them at home.  Golden Ear is a close match to your Def Tech's in sound.

The reason the Legacy's would be far better is sheer displacement, the Signature is more electrical efficient, has much deeper bass then the Focals. How many sub $10k loudspeakers are rated to 22hz +/-3db and are 93db efficient?

Most high end loudspeakers that are in this gentleman's price range will not be able to fill up such a large room with sound. 

So if you like rock and have a big room you need a speaker capable of playing loud and most loudspeakers from B&W, Kef, Focal, Vandy just won't handle this type of application. 

Bill Duddleston designs speakers that play loud and fill up big rooms, he favors displacement, hence his speakers use  two large 10inch bass drivers going up to 12 inch drivers in other models.

Dave and Troy
Audio Doctor NJ Legacy Audio Dealers

Lots of great options out there. Thank you for everyone who has been giving valuable input. I will reapond to individual posts when I have more time. For now keep the ideas coming. 

Proac 140 Mk II or Proac DT8