I bought a scrapbook photo holder for my circs. I got it at Michaels. The case holds 16 or 18 (I can't remember which) 4x6 smaller plastic cases that are for photos. I can get 2-3 smaller needle sets in each of the 4x6 boxes. And one of the larger size needles.
For the straight needles I also got a scrapbook type case that had dividers width wise. The only ones that don't fit are my really long old metal ones. I also use them for my DPN's and crochet hooks. I have 2 of those one for straight needles and one for DPNs and crochet hooks. So far they work great.