I think if you're wearing a PC with a white wingtip shirt, and a white fur sporran then white hose would be your best matching option. I think black, or blue, or green or whatever matches your kilt may work, but it seems to me under some circumstances that white or cream is your nicest option. I have lots of hose, but my formal sporran is white, and while wearing a white wingtip, white hose seem to go perfect.