Originally Posted by suzeeq
Needle size depends on the item you're knitting and the yarn weight. Socks would be better on size 1 or 2s, though if you're a tight knitter you may need 3s.
Sock can be knit in varying yarn weights not just Fingering weight yarn. The needle size would depend more on yarn weight and your gauge than the item being knit. I am currently knitting kilt hose (knee high socks to be worn with a kilt) in sports weight on size 4 needles and could have used size 5s. There are a lot of patterns for worsted weight socks using size 5 to 6 needles.
Look for a pattern you want to knit, select the yarn you will use and then pick out the needles. Pick the size recommended and have fun knitting your project.
Evaluate the needles - did you like the needles material, did you like the needle length, did you get the gauge you were expecting?
Having knit your project and evaluated the results, look for a second project. Will the needles you have work for the new project? Do you want to try needles made with another material?
Get a second set of needles, if necessary, or do a second project on the original needles.
Repeat the knitting and evaluation and getting new needles until you have 8 or 9 set in all possible sizes. Once you have reached this point go to the yellow pages and find a chapter of Knitters Anonymous