With shrinking feature size of silicon fabrication technology, architects are putting more and more logic into a single die. While one might opt to use these transistors for building complex single processor based architectures, recent trends indicate a shift towards on-chip multiprocessor systems since they are simpler to implement and can provide better performance. An important problem in on-chip multiprocessors is energy consumption. In particular, on-chip cache structures can be major energy consumers. In this work, we study energy behavior of different cache architectures, and propose a new architecture, where processors share a single, banked cache using crossbar interconnects. Our detailed cycle-accurate simulations show that this cache architecture brings energy benefits ranging from 9% to 26% (over an architecture where each processor has a private cache).