With that tartan, and excellent choice of Rugby shirt I would say you could go for navy or purple hose. I have done it before with the Scottish Rugby Jersey and my x-marks, and Isle of Skye kilts, it will look great.

I forgot to say you could check here for different coloured hose, I have used them before and they get them to me in about a week. While they are not the most luxurious hose on the market they are good value for the money.