How does the room sound when you clap your hands? Walk around the room and listen for ringing spots. Sometimes those angled ceilings are really bad, other times not. My last home living room had a gabled ceiling and most of the room sounded fine but there were two places where celing slap was bad. Fortunately those weren't desirable listening spots anyway.

If it's going to be a dedicated listening room, you could always add absorbent wedges to the walls. If you don't want it to look so much like a studio, maybe bookshelves as diffusors would be better. I find those kinds of decisions are sort of made for me. I have to work with the room, as they always serve as both listening rooms and living spaces.

For the bass end of the deal, maybe add a couple subs if the room modes make too much boom or suck out in spots. The multisub approach really works well. Some rooms don't need it as much as others.