We tested three single-chip ISM-band radio transceivers with an eye toward communication system-level performance in wireless sensor network applications. We compared the performance of an older-generation chip (Texas Instruments TRF6900A) with two recent chips (Texas Instruments CC1100 and Analog Devices ADF7020). To understand packet-level sensitivity and the potential gains of forward error-control coding, we evaluated the packet error rate and bit error rate statistics as a function of received signal power at two data rates. We characterized features - automatic frequency control, digital received signal strength indication (RSSI), and digital transmit power control - of the two newer chips. We also modeled and evaluated their current consumption and energy efficiency (in terms of per-bit energy use). We found that the new-generation radio chips have significantly higher integration and overall performance, and that radio chip selection for wireless sensor node design is application-dependent. Our work can be used as a design pattern for further testing of additional and future radios for wireless sensor network nodes.