Significant levels of heat are generated in contemporary electronics, and next generation devices will continue to demand higher power despite decreasing size; therefore, highly effective cooling schemes are needed. Simultaneously, advances in metal additive manufacturing have enabled production of complex heat transfer devices previously impossible to traditionally manufacture. This paper introduces three novel prototypes, originally designed for a prior ASME Student Heat Sink Design Competition sponsored by the K-16 (Heat Transfer in Electronic Devices) technical committee, to demonstrate the abilities of selective laser melting processes in the fabrication of A357 aluminum, EOS aluminum, and copper heat sinks. The performance of each of these prototypes has been determined experimentally, and the effects of specific material and design choices are analyzed. Comparisons of experimental results show that the copper and EOS aluminum prototypes performed better than the A357 aluminum due to increased thermal conductivity; however, the gains in thermal performance from EOS aluminum to copper were much lower despite the large difference in thermal conductivity.