I agree with Kurt, if you don't need SACD and redbook digital is your only source, grab a AA Capitole II and skip the preamp.
If looking for a balanced tube preamp, the above mentioned BAT's, ARC's and Atma-sphere's can all be added to your list.
FWIW, have you tried the Marantz w/o the Bel Canto DAC?
I would think that cd player would sound better w/o the DAC.
I have a BAT tube preamp with my Jeff Rowland amps (Model 6 monoblocks), and it sounds great. I also have a highly modified Marantz SA-11S1, and don't feel the need for a seperate DAC. I use a preamp because I have 4 sources.
I also love the way the Marantz handles SACD's. If I was rebook cd's only, I'd definitely go after a Audio Aero Capitole and skip the preamp.
John