I agree with Landroval but would add the Pioneer Elite vsx52 from dynaco.com at $539. Great price on a very nice receiver. A coworker bought the Elite vsx59 from them and had a very good experience. Full warranty and very fast shipping. Any of the three are good matches with the BA's.
Some people may not agree with this but I have the same Boston Accoustics set up that you have and have recently purchused a Denon AVR 2805 and i absolutely love the combination, The sound is very very slightly on the bright side but extremely detailed, when compared to the Yammy I was previoulsy using