Answer:
(got a 100%, 4/4 points)
I personally think Thompson was most important. He discovered the electron and improved hugely on the atomic model with a positively charged sphere with negative electrons dispersed throughout, and the atom with a neutral charge.
I think that without him, Rutherford wouldn't have done his gold foil experiment. Since Rutherford discovered the nucleus is positive, Bhor was able to find electrons have energy levels and that wouldn't have happened without Rutherford, who happened because of Thompson.