Actually, there's a vast amount of possiblities in sub/sat combo's that can sound fatastic! The trick is obviously you need some excellent sounding monitors and a worthy sub(there are lots of both out there) as a foundation. But then, just as, or more importantly, the trick is in THE SET UP!!!!
Where as most full range monitors are already crossed over perfectly(for all intents and purposes), in pefect phase(if designed as so, likely), coherent from a propegation of sound stand point(if designed as so), and are well balanced from the manufacturer! There are lots more "USER VARRIABLES" to consider with a sub sat system! But when you get it right, it can sound as good or better than any full range speaker system!
That all said, the real question you might have asked would be "has anyone heard an outstanding sub/sat SETUP?!!!!" because the combiation of gear may have TREMENDOUS potential, but it might never get set up well enough to MEET THAT POTENTIAL! That's my experiences anway.
So, concluding, I would say that most any high end/higher fidelity loudspeaker and quality sub(within reason) should be able to sound extremely good if you can set things up correctly. Again, however, where it usually falls short is likely going to be the set up execution. And if you're talking about music only purposes, there's other variables....because HT is another consideration entirely.
