There is often an uncomfortable and artificial hierarchy amongst theorists and experimentalists.  Those exalting pure theory often forget that applied science is an art unto itself as is engineering.  There are many problems in applied science or engineering in which theorists are ill-equipped.  Of course, there are rare examples of great theorists who were also great experimentalists such as Fermi.  Steven Quake describes some examples of the crossover between pure and applied science and the scientists behind these initiatives.