If you like the Bel Canto sound, which tends to be very neutral, holographic, extended, and lush, you'll probably get it best with a BC pre-amp to match the amp.
But the nice thing I find with my ref1000m amps is that they are very transparent, so you can easily achieve other flavors of sound you might like with other pre-amp lines. The Audio Research sp16 tube pre-amp I use normally with the BC amps add just a touch of tube like presence in the midrange, which is not something that I think is an inherent characteristic of teh BC sound.