For a supersoft velvety summer scarf I recommend King Cole Bamboo Cotton DK, which comes in a variety of strong, bright colours (slim summer scarf on the left is in purple, shade 524 - and I only needed one skein!). If you prefer something more snuggly warm, then any wool DK yarn will do, and you can see an example here.
Overall I find this pattern so versatile; you can make the scarf any width you like, from long and slim to wide and wrappy. And of course in your favourite colour! It would also make a lovely gift!