I had the Definive Technology BP20's and the Powerfield 1800 sub in my home theater for a long time and I was very happy with the sound for home theater. Definitive has a variety of good matching center channel speakers and surrounds. I had the CLR 1000 for a center and was very pleased with its performance because it uses the same 5.25" drivers as the BP20's, (and 2000, 3000 etc) so the bass from the center made for natural sounding male voice. My friend has the B&W setup but I found many of the B&W center channel speakers are smaller and sound very thin in comparison. The HTM1 center is very nice, but expensive at $2000. Although I was happy with my Definitive setup for home theater, I had grown to hate listening to music on that system. I recently switched to B&W Nautilus line which was many steps up from my previous setup so now I am happy with music and home theater.
I guess it would depend on your priorities. The Definitive stuff with the built in sub saves space and does a good job for home theater stuff and there are a number of very good and more affordable center channel speakers to go with it. The B&W stuff is better for music. The CDM-NT series is really an excellent value and perhaps the center channel for that series would be good - I haven't had a chance to hear that. If mixing music and home theater is important then I'd lean toward the B&W stuff. If its going to be primarily home theater, you could probably get more bang for the buck from the Definitive Technology stuff.
I guess it would depend on your priorities. The Definitive stuff with the built in sub saves space and does a good job for home theater stuff and there are a number of very good and more affordable center channel speakers to go with it. The B&W stuff is better for music. The CDM-NT series is really an excellent value and perhaps the center channel for that series would be good - I haven't had a chance to hear that. If mixing music and home theater is important then I'd lean toward the B&W stuff. If its going to be primarily home theater, you could probably get more bang for the buck from the Definitive Technology stuff.