What is a good all around high quality speaker to purchase?

I’ve heard great things about the MOFI Sourcepoint 888 and,much more expensive, the KEF blade floorstanders.  
 

I’ve heard the Tannoy Stirling speakers which sound incredible to me.  I believe that the treble is adjustable depending on the room.  They have more expensive models too, that are larger.

Take your favorite one or maybe that one you still have get a crossover speaker improvement kit for that model from GR research in Texas have it done or do it yourself to the speaker and enjoy.

it will be the best it could possibly be

hard to quantify but let’s say you could make it twice as good as it was before that’d be pretty significant wouldn’t it?

Try it if you don’t like it sell it!

So far he has improved several speakers I sent him Yamaha ,Sony and they are so good now, so much improved that I would keep them and I could enjoy them and several of these were not expensive high end  speakers.

So when you start out with something that's pretty good to begin with it's even more impressive when it brings a smile to your face instead of a frown or a headache

Yes it was worth the money imho

… and the Tannoy cabinets are like a work of art.

I would also think about the floor standing PS audio speakers.  It would make sense that they pair well with your equipment.

audiotroy - Legacy Audio speakers were my grail 25 years ago.  I heard the Whisper speakers at a demo in Houston and they were the best sounding speakers I've ever heard.

One overlooked piece of the puzzle is how well the components play with each other.  Brightly voiced speakers (like your B&Ws) driven by transistor preamps and amps can be harsh and glaring.  Smooth-voiced speakers like Sonus match better with transistors.

Alternatively; the McIntosh tube products are voiced much like the Sonus and together sound muted and mushy (sorry, just my opinion).  However I have heard Macs driving Maggies and it was remarkably good- and I'm no fan of Macs. 

So the above wasn't a direct answer to your question. Here's mine: Go to a HiFi shop or a HiFi club nearby, or to a friend's house that has good gear and give your ears the right to vote. Match strength to weakness to balance out your sound. Don't forget your listening room's demands. This will color your sound as well.