You can now see profiles of famous scientists on Google Scholar citations. Here are links to a few of them (via Ben L.). Von Neumann, Einstein, Newton, Feynman
But their impact on science pales in comparison (with the possible exception of Newton) to the impact of one statistician: R.A. Fisher. Many of the concepts he developed are so common and are considered so standard, that he is never cited/credited. Here are some examples of things he invented along with a conservative number of citations they would have received calculated via Google Scholar*.
A couple of notes:
I think this really speaks to a couple of things. One is that Fisher invented some of the most critical concepts in statistics. The other is the breadth of impact of statistical ideas across a range of disciplines. In any case, I would be hard pressed to think of another scientist who has influenced a greater range or depth of scientists with their work.
Calculations of citations #####################