In the past few years, the enterprise computing technology has changed dramatically. Virtualization, SaaS, and cloud computing are creating fundamental changes, and leading to an time in which enterprises distribute critical IT applications across multiple service providers and infrastructure. These changes are rendering legacy monitoring tools, which have their roots in the computing environments of a decade or more ago, virtually useless. This paper explores today’s computing trends and their monitoring implications. In addition, it reveals how a new monitoring paradigm, the NMSaaS architecture, uniquely addresses the monitoring realities of today’s and tomorrow’s enterprises—whether they rely on internal platforms, external service providers, or a combination of both.