Our hearth room has a similar cathedral ceiling with massive beams, and it gets lots of light thanks to a wall of east facing windows plus south facing french doors. Both the walls and ceiling are painted Manchester Tan. It's actually the one room in our home where I really like HC-91, probably because of the light. Elsewhere, it seems a bit blah. No offense meant to anyone who loves HC-91, it's just that our previous homes were filled with lots of color and this was a huge change. I expected to repaint the entire house, eventually, and if I ever do the hearth room won't be changing.

Wow, looks like the Ponderosa Ranch on the old show Bonanza! Time for a change. I would start with painting all the wood panelled walls and window frames (advice given above re. primer 1st is key) One of the nice thing about wood walls is that you can hang a painting anywhere you like. Change the lighting to something modern and brighter. See how you like it at that point. Personally I would paint everything as the beams look too small to be interesting and the wood panelling isn't that interesting.I would go for a rustic Swedish country look which would be not that much of a stretch with your great rustic house. The furniture layout looks like it could be tweaked a bit as well. And just curious about the stair railing? Is there glass in between the posts or is it really empty space?

Do everything except trim in flat. I was skeptical when my paint contractor suggested this, but it’s turned out well. Flat is no more difficult to clean and is easy to touch up. Also, flat minimizes flaws and that dappled texture that annoys some people.

I always use bright white for ceilings due to this color helping to add light into a room. I then opt to get my ceiling "color" from the light fixture, which gives me what I believe is more freedom to choose what I like, rather than what's "recommended."