This is just me, your personal taste & objectives may differ. I'm not big on some single, huge art in my space. In the past I decorated a couple large rooms that had decent light & lighting (which I payed attention to and enhanced). I created a couple of large mirror spaces in asymmetric locations that helped enhance the lighting and expanded the perceived space in coordination with the windows. I also am into plants and had a number of healthy and unusual specimens of differing sizes, colors, light needs.
Once I had the space so that it was both cozy and had an open feel, like I was semi-outside, then I placed several pieces of art in strategic, non-pretentious locations. Several were paintings and quality prints, but also a textile weaving (from Peru that was both very ethnic and modern in feel) and a couple of semi-flat/semi-3D wood carvings that hung on the wall.
In the end, after most of a year of arranging and moving stuff around, I had a very dynamic 3D space with lots of textures and a spectrum of natural, earthy colors with about 3 distinct complimentary themes controlling different zones of the room. You could sit in several different locations and get a very different experience from each. Between the mirrors and windows, you felt like you were in some sort of a treehouse or beach pagoda with a wide vista to catch the eye in every direction.
One single, large mirror about 3 feet by 6 feet, the other a set of 6 mirrors about 18 inches wide and five 5 tall. I staggered them so that some were about a foot higher than the others, with narrow ~4" gaps of bare wall between them. The entire arrangement acted like a single mirror, but with a very dynamic feel. There were also a couple of small mirrors, like ~ 1 foot x 2 feet and another about 10" wide by 3 feet tall in dark corners that helped make the space feel open.
Almost all my interior lighting is always directed at the ceiling or walls or art pieces for zones of ambient light.
