The last decade has seen several changes in the structure and emphasis of enterprise IT systems. Specific infrastructure trends have included the emergence of large consolidated data centers, the adoption of virtualization and modularization, and an increased commoditization of hardware. At the application level, both the workload mix and usage patterns have evolved to an increased emphasis on service-centric computing and SLA-driven performance tuning. These, often dramatic, changes in the enterprise IT landscape motivate equivalent changes in the emphasis of architecture research. In this paper, we summarize some recent trends in enterprise IT systems and discuss the implications for architecture research, suggesting some high-level challenges and open questions for the community to address.