I've recently started using CodeSmith, which has saved me a bunch of time already. Today I was fiddling about with some XML schemas, and needed to generate a load more with one change in four places. As I dislike copying and pasting involving lots of files and intricate mouse selections, a quick and dirty CodeSmith template did the job.
It took about 4 minutes to create the template, and using it is enjoyable. The alternative would have been unenjoyable. Thus, using CodeSmith is enjoyable.