I used DPNs. I have a short cord (16") for an interchangeable circular needle set (Hiya Hiya Sharps), but the length of the needles is far too long for the cord, and it's almost impossible to knit something with a 8" circumference.
I'm not a diehard for DPNs, but I can't justify yet one more knitting purchase for FlexiFlips, which is the exact kind of knitting device I would prefer to use for socks.