I have the new KLH model 5's and am using a Luxman L-509au with them. It is 110 watts per channel and it is more than enough. My room is only 10' 8" X 16' 6".
I have had these speakers for a while and thought they were pretty good. But once I positioned them correctly and did some room treatment they have really come alive. These are much better speakers than I originally thought. Setting them up correctly is critical for your room is critical.