One, inexpensive way to work with a large wall like this is wallpaper. Wallpaper can be used no matter the size of the room and comes in so many styles. You can create whatever image or mood you are seeking in the room will wallpaper.
Don't let working with wallpaper scare you. Use the following suggestions when you decide you would like to decorate with wallpaper.

Room Prep
Preparation is paramount to achieving a good outcome when working with wallpaper. Most of the horror stories you hear about wallpaper results were due to lack of proper preparation. Just as when you go to paint a room, a large portion of time will need to be spent on preparing the wall.
You need to take all switch plates, outlet covers, and anything hanging on the wall down, prior to wallpapering. Sponge the wall down to eliminate any dirt and allow it to dry.
If there is any damage to the wall surface like holes or lumps, fix them with a drywall or spackling compound. After you apply the compound, level it out and allow it to dry completely. You will need to sand this to allow the wallpaper to stick properly to the wall. Now, you apply an acrylic adhesive to the wall.

Make sure you take accurate measurements of your wall and purchase extra wallpaper to use for errors and in matching up patterns.

Hanging the Paper
After you have applied the adhesive you need to make a decision on what direction you want to work when hanging the paper, i.e., right to left or left to right. You may already have cut your paper, but if not, cut it into strips which will allow the pattern to match up. You also want to leave room at the bottom for a bit of waste. Starting at the top, apply the paper to your wall. If you have holes to work around, like where the switch plates or outlet covers are, it is easier to begin laying the paper over them and then cut out a hole vs. trying to measure where the hole will be and pre-cutting this into your paper.

The biggest mistake first time wallpaperers make is how they deal with air bubbles or paper that is not attached evenly to the wall. Don't run a plastic smoother over the paper as it can tear the paper. You should take a clean soft cloth and use it to gently apply pressure. You can also use a small rubber squeegee like you would use when removing access liquid when cleaning windows.

Wallpaper Designs
Using wallpaper allows you to use colors and patterns that would not be possible with paint alone. You can opt to use a wallpaper with patterns or stripes if you are working with a large wall and don't want it to appear so large. If you would like the visual effect of added height to a room you can pick a paper with vertical strips. Likewise choosing a paper with horizontal stripes will make the room appear wider. You can use more than one paper as well. If you have a chair rail, you may choose to have a striped pattern above the rail and a solid or print pattern below.

If you want to use wallpaper in multiples rooms in your home you can still create a fluid look without having to use the exact same paper. You can create continuity by using various tones of the similar colors or comparable patterns.
You can create various moods with wallpaper from ultra formal dinning areas to informal play rooms. As wallpaper comes in every imaginable color, pattern, and theme, don't be scared to work with it, but allow it to help you create the look and the feel you really desire in a room.