how about a darker grey or lighter for the one wall you will paint? Black, slate,cream or white curtains?

I was wondering what colours would go with grey walls in my bedroom? My walls are grey, but I want to paint one wall (the one which my bed is leaning on) and I don't know what colour to paint it.. Also I need new curtains because at the moment they're lime and I really want to move away from the green in my room.. Help?:)