HavingFun
I think you are on the right track; I have B&W speakers and a Rotel amp myself and absolutely love them.
As you move up the loudspeaker food chain, you are mostly paying for bass response and the ability to play loudly cleanly. At moderate volumes and with midrange heavy material (eg. voices), it's hard to tell the difference between say, a $3 000 pair of speakers vs. a $10 000 pair. With that in mind, I would say get the best speakers your budget can comfortably handle, then add a quality subwoofer later.
Good advice about buying used, as that is how I managed to score my B&Ws. However, I would add a couple of caveats:
You have to know the market a little bit, because high-end audio is a lot like the car business, and to make a car analogy, you might end up paying $30,000 for a BMW 750iL thinking you got a deal, only to find that features that used to cost a lot of money are now standard in the newer cars and so are a lot cheaper. On the other hand, you could get some speakers that are still currently being made at a 20-25% discount.
Talking generally, buying used speakers is pretty safe (but again, know what you are buying so you don't get something too old), but used electronics is more of a crapshoot because features change so fast. It wasn't that long ago that progressive-scan DVD players were only in the high-end and costed thousands of dollars. Now you can get them for a hundred bucks. Same with HDMI video switching, etc.