I would put up a large painting, if you can afford it. If not, you can do a large mirror, or wall piece and backlight it with LED's.

Go to Etsy.com use their search engine. Artisans and Craftsman from all over US and world. Input photography and what you like. Also have paintings. I have a shop with high def photography, nancyhehman. I can customize to suit your needs. Different media or sizes. High definition photography is almost as good as being there!!

Hi. Here's a link to one of my favorite sources for art. You can search by size, price etc. All original pieces by up and coming student artist.
http://www.ugallery.com/price-100-300-dollars/size-three-to-four-feet
Good luck!

Hi, first off what is your style? hard to tell without knowing you, what furniture you have right now and which direction you want to go. Remember less is more, and not all walls need to be "filled" sometimes accent paint colors in simple grays/taupes/mettalics can make a statement, or even orgainic wallpaper like a linen, would add dimension... without going overboard with "decorating" good luck

I agree with one single piece of art work that is in proportion with the size of the wall.