Black - although you wouldn't want to paint the whole room at that.
Dark Blue
White is usually a nice contrast
Red
I remember when we were in school our football kits had purple and yellow jerseys.... yeah we hated them.
You could always paint the curtain wall a different colour to the rest of the room.
Darn. I thot no one else would talk about white.
It all depends upon what mood do you want to be in the room. If you're trying to brighten up the room, make it less gloomy, then white would be very nice. Do all the walls white, and i would choose a soft white. Not antique white, there are some other whites that aren't bright white, but also not a creamy white.
Those would be great, and then the dark purple curtains would provide the neat contrast. And as others may have said, you could also get other purple accents like bedspread, pillows, to be accents to the dark purple curtains.
The white walls would obviously brighten up the room, but still allow the dark purple curtains to not darken the room too much.
A light purple would look great with dark purple curtains.http://www.benjaminmoore.com/en-us/paint...
White accessories will look great .
I think Teal or cyan or light blue would go great !