Are they structural or decorative? If not structural it could be time to remove them and replaster a more contemporary ceiling. Or you could clad them in a gorgeous recycled timber to give them a more organic solid look. Easiest way would be to continue the charcoal paint to the beams... but lighten the feature wall to a complimentary steely gray. Some chunky timber shelves either side of the stonework with books, ornaments and lighter pictures with a pop of colour will soften it.

So, who wants to take my $10 bet that someone will get on and tell you to paint instead?! lastly, I recommend you look at solar tube skylights as a cost comparison to a full refinish. It would lighten up the whole ceiling and room, with little heat gain, and a saving on light bills.

Most timber stains will look good but I would go for a mid brown stain. Look at kitchen photos here on house - search white kitchen with timber floors. I just checked myself - when you enter white kitchen and timber floor- the majority of photos have medium tone (35000 images ) and only 15000 images or for dark timber and even less for light tone timber.

I came across your post and I think we have the same house! I was just pondering whether to paint or not. What was your verdict on painting the beams? I was leaning toward preserving the mission brown.