For knitting socks...for magic loop style of knitting socks, the cable should be very long and very flexible.
You can also knit socks using a set of 4-5 double point needles, commonly referred to as dpn's.
I'm not a sock knitter personally. I'm sure others will weigh in on their favorite style of knitting socks, and the needle brands they prefer.
IF I were gonna start to knit socks, I'd use Knit Picks Harmony dpn's. If I got really good at knitting socks, maybe I'd invest in Signature Needle Arts dpn's. I've seen Eunny Jang knitting socks using them...and they look fantastic.