I suppose I can't talk about ZMB without first discussing ZBB. ZBB is Zero Bug Bounce - the moment towards the end of the product cycle when, through fixes and triage, the bug count reaches zero. Usually at this stage, additional testing or research (or regression) causes a few more bugs to show up (the "bounce". Eventually, the bounce stops, the bug count stays at zero for some time, and you ship. Something tells me I should have done a much longer post on this concept, but I'll leave that for another day (or for someone else).
Something I strive for (and few others as far as I can tell) is Zero Mail Bounce. I try to keep my inbox count at zero. That doesn't mean I check email constantly - it just means that once or twice a day I try to go through my inbox and deal with everything I can, and queue up the longer work items in another folder. Sometimes, things get hectic and I get behind, or can't deal with everything
Yesterday, for example, was a bad day, and I got behind. Although I have seen dozens of inboxes with hundreds or thousands of items, for me, 19 items in my inbox is way too many (btw - inbox count was to zero before I went to bed)
Of course, I make the whole process a bit easier for myself. Only mail sent with my name on the "to" or "cc" line, mail from my manager, or mail sent to our team alias makes it to my inbox. Now, only mail that may result in action needed by me will get my regular attention. Everything else is for reading at some other date, days or weeks in the future.
I should mentiont that, while I am a fan of getting things done (lower case), I am not a fan of David Allen's Getting Things Done (GTD - capitalized). To be clear, I like organizational concepts, I just don't like the book or some of Mr. Allen's approaches.
One thing I do like is the do it, delegate it, defer it approach to email. When I review my inbox, for each mail, I either take care of it (reply, do something, etc.), delete it, or - if it will take some time, or if it's something I can't do right away, I move it to my "Work" folder (some other stuff gets moved to a "reference" folder - e.g. stuff that may be valuable at some point). My "work" folder currently contains 12 items - it typically fluctuates between 5 & 20 items, and depending on what else I'm working on, I usually try to keep it in single digits.
For me, this system keeps me organized, and it ensures that I don't forget to do things. There are plenty of things I don't get to soon enough, but everything gets dealt with eventually.