Many good masters programs offer the flexibility to choose your courses and research area - with guidance from your advisor. I think you need to decide if you want to grow your technical skills and augment them with management skills or if you want to focus on management but sharpen up your technical knowledge.
If you want to focus on management - I would go for a Masters in Engineering Management or similar program and just make sure you are taking the technical/engineering courses you would like to keep your technical knowedge sharp.
If, on the other hand you want to really grow your technical skills then get a computer science or computer engineering Masters but throw in some engineering management courses.
When all is said and done, what you really should get out of finishing a masters program is a significant boost to your self discipline, your ability to learn indepndently, your ability to perform research, and your ability to communicate. The specific courses will be helpful in the short term but the soft skills are what will really help. Pursue what genuinely interests you (and make thatyour first priority) and you will definitely find ways to apply it in your professional career - if your like the most - your career will twist in turn in directions you can't even imagine now - so following what interests you most when furthering your education is your best bet.