My first inclination is to say something more rustic, in keeping with the post and beam. However, I think there are different styles that would work. More than a particular style I would think more in terms of keeping it more casual regardless of which style you choose.

Post and beams come in many styles. Is the house in question a mid-century modern or is it something more rustic? Photos would help.

We built the house. 18 years old. I would say more modern but we are gradually doing an entire redecorating/remodel. I'm beginning with the powder room because it's a small project and I'm not good at this. I thought it would be a nice warmup.