I'm knitting mine in a yarn recommended by Jasmine at knitting group. Its a superwash merino aran weight from Dream in Colour.
Its a hand-dyed yarn and they use a technique called Veil dying which gives a slightly mottled effect... im using 2 skeins at once to try to maintain some consistency in the colour. This colour is called Gothic Rose and it's rather darker than I expected - this is the downside of buying yarn online of course. I bought it from the excellent-ly named website www.sonnyandshear.com/