To be a great teacher, you must have it all. At least, that is the basis behind the TPACK model.
TPACK stands for Technological, Pedagogical, And Content Knowledge. Great teachers must possess all three of these qualities.
Technological - Teachers must know the technology options and use what is appropriate. The age-old saying "Don't use technology for technology's sake" applies here. A great teacher knows what technologies, tools, hardware and software are available. They choose what makes sense for the pedagogy and content knowledge. They do not use a technology just to use it. All technology used with students must have a purpose.
Pedagogical - Teachers must know the best methods on how to get learners to learn. Classically trained teachers know this well. Teacher entrepreneurs may struggle here. There are too many theories to list on how people learn but great teachers know them and apply them.
Content Knowledge - Teacher entrepreneurs, high school teachers, higher ed teachers and adult ed teachers usually have this one covered. If you are an elementary teacher, you may struggle with this one. You have to know your subject so that you can make appropriate choices for pedagogy (andragogy if you are teaching adults) and technologies.
These three qualities work in concert to create the best learning experience for the student. Each quality interacts with the other, so understanding how technological and pedagogical decisions work together is just as important as knowing how pedagogical and content knowledge work together. This idea is shown in the image below.