The needles I select, depend on the type of garment or project I am working on. See also: "Knitting with Circular Needles" and "Knitting Needle Size Cross-Reference Chart."
Socks. When Knitting socks I usually use 2 different needle sizes, although sometimes I also use a straight needle for casting on. For fingering weight yarn I use the following needles:
2-3/4 mm straight (1) needle for casting on (optional)
2.5 mm circular needles (2 pair 24" long) for sock body & instep
2.25 or 2.5 mm DPNs for cuff ribbing (4 needles)
Updated June 4, 2012
After I had knit my first pair of socks using two circular needles, I decided to develop alternate instructions to better suit my knitting style and improve clarity. I have to admit that I struggled with some of the instructions in the book that I used to learn knitting socks with 2 circular needles. The steps for the basic sock technique are explained here for a woman's medium sized sock. References are provided for other sizes.
Knitting socks with 4 double pointed needles was neither fast enough for me, nor conveniently portable. During transport in my project bag, stitches would slip off the metal needles I use. When a dog, sitting on my lap, nudged my knitting (aka neck scratching) hand, a needle occasionally slipped along with one or more stitches. Some new tools and techniques solved this problem. Read on.
The hundred mile club comprised a small group of high school students who had run more than a hundred miles in a year; the name turned out to be more daunting than attaining the goal--though it was not a goal that I would have selected myself. With 3 hour-long running classes a week, rain, shine or snow, you hit the target before term was over. Cheating was not an option--the instructor followed you on bicycle.
Hundred mile club socks have hiked well over a hundred miles in each of 3 years. So if you wondered why they didn't look new in the photo, now you know. The socks are going on their 4th year and I'm amazed that the heels and soles have not worn out. With the lives of commercial socks now in months (no longer even a year), this is all the more amazing. As well, I'm more than half-way to the hundred sock club, though like the hundred mile club, this wasn't an intentional goal of mine.