One thing to consider if you are deciding between 4BSST and 7BSST is that the 7BSST puts out more class A watts before going to A/B, although this would be of most benefit with higher effciency speakers - say for example Zu speakers, which have attracted a lot of favourable comments here and elsewhere.. However the 7BSSTs will gobble more energy and produce more heat. Remember that when auditioning Bryston amps, that short speaker cable lengths are best. If you are getting a demo where they are using 30 foot speaker cables, you will not get the best sound these amps can produce. Unfortunately, there are a lot of audio shops that do this.
If you are going into the PMC price range, you may also want to have a listen to Dynaudios. I am using my 4BSST/BP25 with a pair of Dynaudio Confidence C1s and I am very happy. CD Player is an Ayre CX-7 - also very happy.
As for music, I have always found classical to be the best for showing what a system can or cannot do. However, if you are not familiar with classical music, it might not do you any good. The best thing to do is to use music you are familiar with. Get a very well mastered CD so you know that any bad sound is not coming from a bad CD instead of a bad system. Take also a badly mastered CD - especially if you like rock music since so much rock music is poorly produced. If you do go with classical, for your good ones you can take something from Reference Recordings, EMI Classical or Naxos. Best to pick DDD CDs produced after 1995. For bad classical CDs you can't go wrong with Virgin Classics. Probably the worst quality CDs on the market.
Sorry I can't advise you if you are into vinyl. Maybe someone else?