Should you add works of art to your home? Yes, Yes, YES! And, in case you missed that, most definitely, yes. I obviously feel pretty strongly on this subject, but I am a person that believes artwork can express every single emotion and mood, sometimes many of them at once. And I believe having inspiring works around you can make your home more provocative, comfortable, exciting, etc. I also believe that the homeowners or inhabitants should try to include their own art pieces.
So, the next question is what pieces of art should you incorporate? This is entirely subjective and you should add pieces that you like. Some decorators provide homeowners with artwork, some recommend artists and some stay out of it. I think it depends on the homeowner's personality and lifestyle. The uber-rich may not care about the art, they just want the "best". And some homeowners just want pieces that match their decorating style. But I think art should be more than an accessory and you should add what you like. And don't limit yourself to pictures or paintings, consider sculptures, vases and other mediums. Go from the gut.
Finally, how should you display your art. Prominently and proudly. Display your artwork to its best advantage by hanging it properly, use lighting (natural and artifical) to your advantage, and let your art speak for itself.