it's hard to help without seeing what you're talking about, but i like it when the coffer squares are painted the same color as the walls and the beams are left white or cream. i think it highlights the coffers. here's a photo:
http://www.dannylipford.com/images/e...-ceiling-3.jpg
the recess arches would be really nice with a slightly different shade of yellow i think and in the master bedroom i would paint the inside of the tray the same color as the walls like w/ the coffered ceiling and that way it's consisent and also accents the tray celings. here's a photo:
http://www.duluthbudgeteer.com/gfx/p...s/Ceiling1.jpg
this is different but really pretty too: http://www.dallasnews.com/sharedcontent/dws/img/04-08/0405traysmall.jpg (broken link)
i'm sure others will have lots of options and opinions. there's a lot of photos online too. so many options!! it sounds like you have a beautiful house to work with! i'll try to post some more photos for you to see. hgtv has tons of photos, house beautiful, traditional homes, just google coffered ceilings, tray ceilings, etc. and you'll get tons of stuff too.