KEF Reference Model One

KEF reference with Uni-Q are nice clear punchy suckers. You could do worse. $599 seems a tad high for what they are but Ref 2's go into four figures.

Your Denon should be able to tear these to shreds (not familiar with the Yamaha).
I've owned the Ref III.2s but thought the design sort of dated.
For the money you're talking about, I'd look at the B&W floorstanders recently reviewed in Stereophile for around $1000 (list).
If you must have KEFs (I own two non-Ref uni pairs and a Q9c center channel), I'd go with Ref-IIs -much better design than the ones...

P. S. The B&W I refered to, the DM603 S3 just won the Stereophile
"2005 Budget Component of the Year" award.
Listen to me now and thank me later...