This is a screenshot of WhiteStarUML that I use for simple UML drawings. I actually used to create my own CASE tools in earlier days to achieve a higher level of automation, but those tools are build on MFC and I don’t want to continue using MFC as GUI base since Microsoft is not supporting it seriously.
WhiteStareUML is free, open source and written in Delphi. It is quite ok for high level class diagrams. Code generation on these tools tend to be Limited.