The main areas, or focal points, cry out for adornment, and the minor ones would look nice with the right piece, but there's no rush. Let me emphasize something to those of you who love to collect art. I personally believe in empty space. You're not living in a restaurant that is overall-decorated to stimulate the patrons. This is your home.
Art is an adornment.
Absolutely, use photos in your home. My favorite place to display family photos are long hallways where you can create a gallery and add to it as time goes on. If you are starting fresh, doing all the frames the same is nice, but not necessary. What is necessary is to give order to the hangings. Start your hanging at eye level and get all the bottom edges lined up and the side edges whenever possible.