I'll admit it ... I drank the UML cool-aid and thought that someday we'd have code-generation directly from the diagrams (we do in part) and round-trip engineer

I'll admit it ... I drank the UML cool-aid and thought that someday we'd have code-generation directly from the diagrams (we do in part) and round-trip engineering (changes to the code automatically reflected in the diagrams). Since then, I've become a lot more realistic and use the diagrams when they're the best method of communicating a conceptual or concrete thought. I rarely use class diagrams, but I find myself using sequence diagrams and deployment diagrams a few times a month. Occasionally I also use Use-Case diagrams when there's more complexity than can be easily included in a single user story.