Rated 5 out of 5 stars

Great plugin, it makes keeping track of how big my mail boxes are getting a lot easier to manage, thanks.

I wanted zeros removing too (especially from the top level account folders) so I've altered the code.

To simply get rid of zeros, just alter line 9 of chrome/content/main.js and change:
return aNumber == -1 ? "" : aNumber;
to
return aNumber {less than}= 0 ? "" : aNumber;

(substitute {less than} for the less than symbol)

This review is for a previous version of the add-on (0.2).