The best advise I have is recycled - someone passed it to me, and now I'm passing it on to you!
Don't worry about anything but comfort and height when selecting a seat. ANY seat design can be covered in leather, velour, tuck-n-roll pleats, etc. to fit the look of the car. However, the prettiest seat in the world is useless if it isn't comfortable enough for an extended ride (unless you are building a trailer queen).
As for height, you need to make sure that the TOP of the headrest is dang near even with the BOTTOM of the window opening - perfectly flush gives the nicest look in profile. If you had a car with larger side pillars, the headrest can be "hidden" behind that so that in profile they aren't visible at all.
Surf over to ebay and look at the pictures of the rods on there - you'll see what I mean...