Room Ceiling Height for 2 channel listening - is taller always better?

To a point I agree. Just remember that open floor plans are the death knell of a high end audio system.

I am interested in the feedback you get here as I’m in the very early stages of designing a new listening space. In particular, my room will also feature a vaulted ceiling so am trying to figure out how to do this in a way that doesn’t create problems. If the room I am designing is 18 wide by 23 long what would the optimal maximum height of the ceiling be? I can stop the upward slope at a variety of points  and come straight across with a flat section—what height would be optimum given the width and length specified? BTW the speakers will be on the short wall positioned about 4-5 feet into the room. I want the room to work with both dynamic and dipole electro stats. Any feedback is welcome that will hopefully apply equally to the OP. 
 

OP: To your assumption that bigger is generally better I had a friend with lots of experience say this “big room, big problems” to which my experience would largely agree. I’m trying to go as big as I can without losing intimacy in the space or the ability to drop some nice Sound Labs in that will have plenty of room to breath!

A friend of mine is in the custom install business and I have helped him with setting up audio systems in various rooms.  The most problematic rooms were those with extremely tall ceilings and rooms with large open spaces.  It is hard to get decent bass in high ceiling rooms and the sound becomes thin and lacking in weight.  In his own listening room, this friend went through the trouble of installing a structure to lower his 16' ceiling.  I would look to something in the 8'-11' range of height.  

It still boils down to treating that room for that issue. There is no getting away from the 8, 9, or 10 foot problems unless you're a horn guy (which kind of helps) and room treatment. Above 12 feet, lower the ceiling. Open floor plans get some roller panels and or heavy floor to ceiling acoustic theater curtains. You can open or close to dampen more or less.

Regards

16 and 17 are very nearly "square". Map it out, you will find the 16 ft modes are right beside the 17 ft modes. Sloping ceiling will distribute those, but focus higher frequencies. Everything you do has a different effect at different frequencies. 

One benefit of the high ceiling, the extra space can be used to hide as many and as large bass traps as you like. Mike did something like this in his room, only with side walls and cabinets that are angled to disguise the traps built in behind.

If I was doing mine again I would go hardwood, because rugs can be more easily moved around and changed. Carpeting wears and then one day you are looking at removing the whole system to replace the carpet.