This inertial-measurement-unit combines 2 of the best quality sensors available on the market to give you 9 axes of data: 3 axes of accelerometer data, 3 axes gyroscopic, and 3 axes magnetic (compass).
The L3DG20H gyroscope + LSM303DLHC accelerometer/compass sensors are all on one breakout here, to save you space and money. Since all of them use I2C, you can communicate with all of them using only two wires.