I use to have one, it held bits from every sprue I had for my orks. But, I always came across a problem - I could never find what I was looking for. So, after seeing someone else do this I decided to use bags. The bags I use are sealable - a little push together thing at the top, you get these when you order bitz from other sites (not sure where else they are available from though).
So, separating the bitz out into piles I put them into a bag and label it. I use a marker pen, the best I have found is one that is designed for CDs or DVDs, like so:
The ink dried fast enough that there will no smudging of the label. Now, I have quick access to my bitz. I found it much easier to have this organised like so - need an ork head... got a bag of them. No more hunting through my mass of bits just to find one head.