In doing a little searching I found that the majority of people recommend 100% wool. Cascade 220 was mentioned many times. It's a worsted weight yarn, but I don't know where it is manufactured if that makes a difference. Start with the pattern and find the suggested weight and gauge first then look for the wool.
DK is lighter than worsted.
Peace Fleece was mentioned many times- http://www.peacefleece.com/knitting%20yarn.htm