speakers that match well with denon

how much are you looking to spend?

Sorry I will slightly disagree with Darrylhifi. I would move cautiously with the Paradigms. I have the Studio 60s(which I love) and tried powering them with a 110W Yamaha receiver and had exactly the same problem you're describing with your mild mid-range. Paradigms like power. I have since switched to separates which opened up the sound tremendously. The Paradigm monitor series my be a better fit. Depending on the power your Denon has and how loud you like it, I would definitely look at speaker that are fairly efficient 91+dB.

Boston CR8 or similar Boston speaker would be a good match.

Maybe Energy's Veritas V2.2 (with a dome midrange that will have better claity) but will need some power to sound good.
I used to run them with the AVR-4800 but are now bi-amped by two Denon's POA-5200 with are crossovered by a Mirage LFX-3 into two BPS-150i subs in stereo. Now I think they sound great. Still using the 4800 to power the rears (Energy Connoisseur C-6).
Hope this helps.
Rich