I have seen lots of stools that are the wrong height.  It is not the height from the floor that is important - it is the distance from the top of the counter to the top of the seat that is most critical to comfort.  The generally accepted dimension is 12 inches.  Don't make the mistake of buying a stool without making sure that it fits your counter or bar.  Sure you can cut off the legs to get the right height but then the stretcher appears too close to the floor.  

Let me know and I can custom make stools that fit any counter or bar.

Taliesin Batten Co.

Windsor chairs are especially comfortable because of they have a scooped seat.  Just looking at them they appear comfortable. The seats are usually made from a soft wood because it is easier to remove material.

We had some bar stools that never quite felt right.  The seats were small and  flat.  I always felt that I was going to fall off.  

Using the scooped seat idea from Windsor chairs I built a set of stools.  The slight rise in the back encourages you to sit up straight and the gentle slope under your thighs provides nice support.  The shape invites you to sit in them.

This set was made out of cherry and the blank starts as a 3 inch thick piece of wood.