As I noted in a previous question, it is believed by many physicists that when Einstein's general relativity and quantum mechanics FINALLY get married together in some 'Theory of Everything' that there will appear limits on the size, time and mass of physical events in our physical universe. Combining these 'Planck Scale' units one can derive a limiting density near 10^94 grams pre cubic centimeter, and it is believed that this replaces the 'infinite density and curvature' condition predicted for singularities according to the less-complete theory of general relativity.
At least that is the hope.