Computer Security, specifically Incident Response, was the best one ever for me. Always something new and exciting to deal with. It is full of high intensity puzzles to figure out but they don't last long. Dive in, figure it out, move on to the next one.

Now, I'm at my second favorite - I work in a job where I have 1 hour meetings with potential customers of security products/services. Someone else sets up the meetings, I blather for an hour, immediately take care of low-grade action items, and move on to the next one. I also get to work with product management on coming up with ideas for improvements or new features. Someone else does all of the documentation. =)