Selecting a warm, mid to dark tone for a large space generally makes the room feel more intimate. Try rich chocolates, jewel-tones, or deeper yellows/golds.
Selecting a lighter color can be easier if you are painting yourself...easier to blend and can create an airy look. Be careful of making it too bland!
Textured walls, faux painting, and stenciling work really well in larger areas. Try an accent wall for a focal point. It's nice to have somewhere for the eyes to grip on to in a big space.
Not wanting it to feel too intimate? Try a warmer neutral color, such as Sherwin-William's Hopsack or Benjamin Moore's Caramel apple... two of my all time favorite colors