If you really want purple, what you might try is to go for complementary colors on the walls and then have a few select purple things that pop out of the room at you. Red is not necessarily the most soothing color, but of bright colors, red is actually a good one and it does complement purple. Something in the caramels might be a really good choice -- those rich, redder browns stand really well against purple. Then look for perhaps a key wall hanging in that purple that you want, or bed covers. That way, you get the purple, but the walls themselves aren't so activating. You could also paint the four walls in different colors -- for instance, paint the wall where the head of your bed is in purple and complement the purple with another color such as caramel on the other three walls. This gives the room a lot of depth, and also you get an initial visual appeal of seeing the purple when you walk in, but you're looking at the other colors when you lie in bed.
If you want to really enjoy the colors in your room, what I'd suggest is to, either with your computer or perhaps with the paint color cards at a store, pick out not just the one color but about three or maybe four that work together. Then set out to do the walls in one or two of those colors and use decorations that feature the other colors.
For instance, in my living room (generally postmodern), I have a green sofa and a red chaise, and rich brown throw pillows. Those are the focal colors; there are other muted browns, golds, purples, reds, and greens, but you are supposed to notice those three colors right away.
In my bedroom (more contemporary, and slowly being updated), it's more cherry-stained wood and gold as my focal colors.
Now admittedly, pot calling the kettle black, I was too lazy to paint my new apartment, although I probably have about the right amount of stuff going on visually without paint.
