Wasn't much for me to read in My Unit Tests Are Purer Than Yours, but for an excellent quote which points out that integration tests are probably more important the unit tests:
And so, if we heed the saying "a good test is one that finds a defect", then where are we going to get the most bang for our buck? Testing very simple rules in isolation? Or testing this extremely complex interaction of rules within the framework. Obviously the latter is exponentially more likely to turn up issues and thus make for the better test!