JeeNode Micro with TMP102
I really like these TMP102's. It's a digital temperature sensor, talks over I2C, consumes relatively little power during measurements, and best of all, it has a "shutdown/sleep" mode, in which it consumes next to nothing. This is better than powering a sensor from a pin (in my opinion), because sensors tend to consume a lot of power when first powered up (e.g. up to 40mA for 5ms for TH02).
The only gripe is that Sparkfun's breakout is unnecesarily big, given how small the sensor itself is.