I while back I got a little tired of deciding what project to do based on the needle sizes I had available, and since I was on a hat and mitten kick at the time I got myself a complete set of 7" bamboo dpn's in 15 sizes (thanks to my boyfriend and my Amazon.com Wish List). They are really nice needles, but they came in flimsy celophane sleeves that were really not meant for long-term storage. I found the perfect storage container at the Dollar General, but any store that sells school supplies will have it - a hard plastic pencil box. The box is about 8" x 5" by 2" and neatly holds all 15 sets of 5 dpn's (which I've kept in the celophane for over a year, which still looks like new despite almost daily use) with room for a small tape measure and a set of 8 Boye crochet hooks.

The whole box fits nicely in my knitting basket right next to my Boye interchangable circular needle set. I have used a smaller compartmentalized plastic pencil box for many years to hold all of the other knitting necessities like stitch markers, cable needles, row counters, tapestry needles, etc. This year's Amazon wish list (and that wonderful boyfriend of mine) has brought me a set of 15 sizes of 16" circular needles, which will be getting their own pencil box in the near future.
If you are going to keep single point needles or dpn's together in sets with some type of elastic band I would strongly recommend elastic hair bands rather than rubber bands. Rubber bands don't age well - they either turn to goo or dry up, become brittle and break. Gooey rubber bands will gunk up your needles, and broken ones are, well... broken.
