Since you have the B&W setup, I'd recommend you to look at a Sunfire Cinema Grand - the Nautiluses do like to be "fed" properly, and the Sunfire is up to the task, while also giving you the best of both worlds (or at least a decent compromise) for HT and music. You can keep your current amp for the rears and the budget relatively low.
What amp is best?
I am looking for amps for my home theater setup. I have a proceed and a pass dealer in my area. I have nautilus 802's left and right nautilus htm1 center and 4 nautilus 805's in the rear.I am going to be using my denon 5800 for my pre. Which amps do you think would be best for my set up?