What curtain fabric with this duvet cover?

[Sinkingfeeling]

I've recently bought a duvet cover in this pattern for dd's bedroom (she's 8) and want to have some curtains made to go with them. Any suggestions for a fabric that would co ordinate?

i would probably go plain i think
something in either a deepish pink, or the bluey colour?
or, something that just has small spots or something? nothing too overwhelming