I agree with stblgt. Use consistent door sizes, and 6'8" is what you want for 9'. We have that in our current home, and it looks great.

there are a lot of 10+ plus ceilings - great room, kitchen, master bedroom, two other bedrooms, foyer and the study - they all angle up. Some to 17 feet. PLUS, our doors are all 3' wide. So I fearing the 3 x 6'8" will look squat in the rooms with the high ceilings.

Are you sure we shouldn't just go with all 7' doors? Expensive, but in the end maybe worth it?

We're doing 7 foot doors with our 9 foot ceilings, but since we have a 2 story we are doing 6'8" doors upstairs where we only have 8 foot ceilings and there are a lot less doors on our 1st floor than 2nd floor so it wasn't a huge budget impact. I personally don't like 8 foot doors with 9 foot ceiling but I know a lot of people do opt for that so I guess personal preference.

The 1838 house I had an apartment in had 8 foot doors on the floors with 14' and 12' ceilings and it looked proportionate.

I think if you go with taller doors, you're negating the effect of having taller ceilings in the first place.

I would consider mixing them or going all 7 ft. We have 10 and 12 ft ceilings and went with all 8 ft doors. I think there's a huge difference between a 6'8" door and an 8' door in a room with a 12 ft ceiling or greater. Ours aren't vaulted though so I'm not sure how that might change the look. Our friends mixed 6'8" and 8" in their home that has 9 and 10 ft ceilings. They did it well. You can't really see any 8 ft doors from the areas that have 6'8" doors. Not sure how your layout is though.

I vote go with 8ft doors. Hands down. In my opinion it makes a big statement in your home! We have 10ft ceiling except in our vaulted living room and all of our doors are 8ft. I love them.

8 foot doors would look awesome in all the rooms with vaulted ceilings. Just think 8 foot doors will look odd in the rooms with 9 foot ceilings. So that's why I'm thinking either all 7' or a mix of 6'8" and 8'. And it seems like people on here are opposed to a mix. So that leaves us with 7'.

I personally think 6'8" doors look odd with 10' ceilings. Very disproportionate. I would totally get 8' doors...they really open the place up. Frankly, I even think 6'8" doors look a bit short with 9' ceilings. I say this because we put 6'8" doors upstairs because our upstairs has 9' ceilings. The doors look squatty to me (maybe because I am used to the 8' ones downstairs, I don't know.)