B&W makes enclosed cabinet speakers as good as they can be. The entire line is superior for what each model is. PSB is not bad either. But aesthetically, which seems to be of serious convern, the Nautilous 805 monitor is georgeous. Especially if you use the light cherrywood finish, and the dedicated stands. Bass extends to 50hz.
Stereophile rated it 'A' class when it first came out a couple years ago, then more realistically reduced it to 'B'. But it shows how taken they were with it, for what that is worth.
BTW it is not appropriate to use a single woofer. For better integration of frequency range place a sub next to each monitor, near a side wall --roughly in an arch from the listening position. By that they can be very unobtrusive, and with a sculpture or plant on top, even aestheically pleasing.
It would be a shame to power these little jewels with anything other than a distortion free amp. Examples: the vintage Hafler DH-200/220 ($200); Muse 160 ($7-1400); any ATI (probably the best value); Bry$ton (pricy), and Jeff Rowland Design Group (offers a suberb integrated model) tends to be so well built as to qualify as art. No kidding. ONe model comes with an optional plastic cover so the interior can be veiwed. Understanbly. But $8k? It shows how price is not the issue with accuracy in amps. Rather build quality and value.
BTW, to evluate other models, look for:
THD/IMD <0.1% over 5hz-50khz frequency range (the models mentioned are more like <0.005% THD/IMD)
Output impedance: <0.4ohms
If accurate bass response, and 'true to the original' sonic characteristics is not your goal, than I have nothing to suggest, and suppose that it does not then matter what you do, right.
'Regrettably, much misinformation and outright nonsense have been spread to promote certain "high-end audio" products. The power of suggestion works exceedingly well, when listeners cannot trust their own hearing. I recommend to re-calibrate yourself frequently. Listen closely to all sorts of un-amplified sounds in order to recognize and remember natural aural patterns. It becomes an endless and futile pursuit to listen for and try to evaluate differences between speakers, equipment and accessories without a reality based mental reference. (Seigfried Linkwitz) www.linkwitzlab.com