I've always put my knitting in plastic bags. Although I have found it annoying when the needles make holes; especially in the beginning of a new project before I can "hide them" in the knitting. By chance I came across this practical little thing... from Knowknits:
Although I thought it silly (as I can make it myself, right!?), I bought it (together with some yarn from KnitPicks). Needless to say I am VERY pleased with it! It is lightweight, sturdy and increadibly practical for bringing your knitting "on the go"!
The size is just right for a small beginning project like socks, shawls, sleeves etc. As the knitting grows, they are returned to their plastic bags. They do come in different sizes, though...
Mind you - Lilla Stickfrossa have some gorgeous knitting totes as well with a more personal touch.