The pairing of fermions is the underlying mechanism for superconductivity and superfluidity. Ultracold atomic Fermi gases present a highly controllable model system for studying strongly interacting fermions and provide unique opportunities to investigate the stability of fermion pairs. Tunable interactions allow us to study the crossover physics from a Bardeen-Cooper-Schrieffer superfluid to a Bose-Einstein condensate superfluid. Furthermore, the control of population or mass imbalance among the spin components gives us an interesting way to search for exotic forms of superfluidity. In this talk, I will present the phase diagram of a two-component Fermi gas with strong interactions and discuss the nature of observed normal and polarized superfluid phases in this strongly interacting regime.