Justin James thinks the usefulness of unit tests is often overstated, and that unit tests aren't necessarily mandatory for all developers. Are unit tests important in your development work?
Unit testing is a development practice that is viewed as a "must do" by more and more programmers and experts. And yet, I think that unit testing is much less mandatory on smaller teams, non-API/framework development, and for certain types of code (anything non-deterministic comes to mind).
I'm not saying that unit tests are unimportant or useless, but I do think that their usefulness is often overstated, and that they have differing levels of utility to different developers.