Strange that you say your system sounds dull with the equipment you have. I had the same amp and the B&W 601S3 before and never found them dull (in fact it was quite the contrary), and from what I hear, the QED speaker cables are also on the bright side of neutral. So I think you're right in suspecting the interconnects to be the culprit (not too long ago, I wouldn't have dared make this statement for fear of being ridiculed by some hi-fi geriatric).
However, I am fresh from doing a comparison last night between two interconnects, the Merlin Verdi II and the Nordost Black Knight and found the Nordost to be clearly brighter and more exciting than the Merlin, although I found it to cause listener fatique even after a short listen. The Merlin was much more natural in my mind, at the expense of a little bit of detail.
I wouldn't recommend the Nordost to you, as I think it's skewed a little too far from neutral for me to be comfortable with. But what I could suggest is any silver plated copper interconnects, as I've generally found them to be more detailed (the Chord Silver Siren and the Chord Chameleon Silver Plus comes to mind).