Depends on how much you want to spend. Spend more than the Rotel cost in the first place, and your B&W speakers will let you know. Go to tubes instead of solid state, get a different sound altogether.
If you are looking to spend about the same amount, I would suggest you look at these products because they will sound different - my guess is better bass with a little more air for around what you would have paid new for the Rotel. The Emotiva really has the potential to grab your B&W's and make them sing.
Rotel RMB 1565 - Class D 100 X 5 amplifier- will be "faster" than the 985 with tighter bass
http://www.rotel.com/NA/products/ProductDetails.htm?Id=476
Outlaw Model 7125 - low distortion amp w/125 W per channel X 7.
http://www.outlawaudio.com/products/7125_about.html
Super Good Deal Alert! - Emotiva XPA-5 - 200 W per channel into 8 Ohms X 5, 350 W per channel into 4 Ohms X 5, 70 lbs, $799. Read about here:
http://emotiva.com/xpa5review1.shtm