What colour walls should we have?

After having kids I have learnt one thing that is very important (well many, but this one is relevent) ; Do not leave writing implements laying around.
Upon coming home yesterday Kayne informs me that M had got a 'team point' at school. Cue me spending a good 30 mins making team point sheets. Kayne gave people team points - me for washing, daddy for shopping, Lani for 'good talking'. They are now stuck to the living room wall. We put away the pens and things, they start playing with dinosaurs.
After sticking them up I went to sort out some washing. 10 minutes later i hear arguing, as i go into the living they are both stood on the sofa and i see they are fighting over a pencil. Kayne says 'Mummy! I was trying to help Lani put eyes on her faces but she won't let me!!' *sigh* Now she has forced our hand at decorating the living room. There is a meter of pencil wall art above our sofa! We also have the wonderful challenge of trying to pick a colour, i'm not going to attemp wallpaper becausei don't trust any of the walls to be straight or reasonable to hang paper on.
So i go and put some dinner on and then i open the kiddie gate and a few moments later Lani comes wandering to find me. She holds her hand out to me and says 'Oh no, look, blue!' sure enough she hand is completely blue, so are her arms and face, then she says 'oh memma (mummy) look, bear-bear blue'. So obviously one pen didn't go back and i have a teddy to wash again.