What colour should you paint your walls most your stuff is purple pink?

none,but white

Another thought.

Grey, a medium tone, true (or silver) grey would be nice, as would a navy blue if you want a bit of drama.

Black would also work or as a compromise, one wall in black and the other three in silvery grey would really set off the purples and pinks.

Word of advice: do not paint any wall a very dark colour unless you have the permission of the owner of the house. It will take two or three coats to get the deep colour and two or three coats of white to return it to the original look.