We have 9' ceilings and normal stock doors. Ordering custom made doors increased our costs considerably. You can see photos on my blog and there is a link on the right side of my blog that has even more photos.

Here is a link that might be useful: My House Building Blog

Ours are 6'8 with a couple of cased openings that are 8'0 and I think everything looks fine. I did make certain that windows on either side of the french doors in the family room lined up wiht the top of the door.

We have 9' ceilings. Our interior doors are standard 6'8". Our front door and back patio door are both 8' (lined up with the windows).

We have 10' ceilings with 6'8" doors and 12" transoms. Nice visual without the extra cost of a larger door.

We have 12' and 9' ceilings. 12' ceiling we used 8' doors - 9' ceiling 6'8" doors

I should've mentioned that on the walls with 8' doors - we also have 14" transoms above the windows.

We were thinking about one bedroom in particular where there will be an interior door adjacent to a couple of windows and if it would look strange for the top of the door molding to be lower than the window. We do not want to go with 8' doors and it sounds like the 6'8" will be fine.
Thanks everyone for your responses.

I have an additional question. I'll see if I can make it make sense. I hadn't really noticed the door & window heights in the kitchen/dining/den until the room was sheetrocked yesterday. The windows are at 8 ft, there's a large one (5x6ft) on the east wall, and in the SE corner there are two regular sized windows making the corner, also at 8ft tall (sink will be in this corner.) We have a cased opening on the North wall at 8ft, looking through that opening you see a 6'8" door across a small hallway. On the SW corner of the West wall there is a 6'8" pocket door and right next to it on the South wall in the SW corner we have a 8' cased opening. I'm thinking I should lower all the door heights, especially since two bascially are next to each other making the corner of the room. But will that be odd w/ the window height being 8 ft? The window will sit basically right next to the kitchen cabinets and then in the corner there is windows that are also 8ft high.

I have all of my cased openings at 6'8". My kitchen cabinets will be 8' high as well...with a 6'8" cased opening in between them, and also on the end.

I think I would make all the openings the same, but that is JMHO.

We are designing homes right now with 9' first floor ceilings and all 7'h interior doors, 42"w x 7' entry door. All window and door tops will be aligned (trimless) except for one monolithic slider that we are allowing to be 8'h.

7' door height for 9' ceilings.

We presently have 9’ ceilings and 8’ doors. It looks like windows are set near that height as well, though I haven’t measured p. Our last home: 12’ - 15’ ceilings downstairs (except 22 foot foyer). Upstairs 10’ but vaulted ceilings all around. ALL doors were 8’, except front door. I’m not sure of size but it was taller.