Theoretical & experimental physics
There was a time when it was not rare for prominent physicist to leave their mark both on experiment and on theory. Newton being the most shining example. The modern dichotomy, experimental and theoretical physics as two distinct activities first became noticeable in the later nineteenth century.
Maxwell, Boltzmann, Einstein, and Bohr did published experimental work. Lorentz left the Leiden chair in theoretical physics for the Teyler Institute in Haarlem hoping to find opportunities there to do experimental work as well. However, all these men are above all else remembered for their theoretical contributions.
Physicists whose activities were seminal both in theory and in experiment have become ever more rare. Rutherford and Fermi are among the few remaining individuals who exemplify a particular expertise. However, due to the increasing intricacies of both experimental and theoretical manipulations in modern times, it is highly likely that this expertise has become exceedingly rare, possibly even non-existent.