Re: What cables do you use?
Dave: I think that your own experience bears put what we both are saying: your replacement drivers cost much less than new speakers, but made a difference. You could have spent a pile of cash, but gotten pretty much the same results.
I believe that speakers are subjective, not absolutes (again, once you pass a certain level), & whatever sounds good to you sounds good to you - some people are fond of a bassier sound, some are not. It also depends on what you listen to - while any good speaker will reproduce accurate sound, some are better if you listen to jazz, some are better if you listen to classical, etc.
(I've heard this said, in particular, of B & W). What it all comes down to, in the end, is your own preference.
Your listening environment also has a profound impact on the speakers you are comfortable with. The same speakers will not sound equal in different rooms. (I think many people ignore this - the speakers that sound great in the showroom may not impress you in your listening environment.)
I say this only from experience - I've helped a few people set up their systems, & found that they were really not aware of the impact that "hard" & "soft" rooms (or furnishings) have.