Emerging data-centric workloads necessitate systems with highly scalable storage components, not only in terms of capacity, but also in terms of performance and energy efficiency. These requirements, in combination with advances in Storage Class Memory (SCM) technologies, will drive the departure from traditional memory and storage architectures. The focus of this paper is on systems that employ Phase-Change Memory (PCM) to either complement or replace traditional media such, as HDDs, protected DRAM, and Flash. We study possible uses of PCM across the entire stack, and present an analysis of the implications this has for the various components, such as the main memory subsystem, storage subsystems, operating systems, filesystems and databases, as well as of its impact on the overall system architectures. Key problems introduced by the new medium are identified and solutions are outlined, which, we believe, will be very valuable for the designers of next-generation data-centric systems and applications.