Fast sensor readings
For multiple sensors, an assortment of analog and digital, a simple solution would be to use an Arduino Mega with a "Mega Sensor Shield" (bottom of page) ($11-12) attached to it. DfRobot offers a Mega Sensor Shield with XBee connector on board ($18-20), which might be even more useful:



This combination allows different sensors to be plugged in, as each of the 54 digital and 16 analog IOs of the Arduino Mega are brought out to separate 3-pin headers consisting of signal, ground and Vcc (5 volts). Thus sensors which need power would also receive it from the Sensor Shield. 

As the Arduino boards themselves cannot provide more than 200 to 500 mA per board, depending on the board specifics, the Sensor Shield also has a connector to accept power from a wall-wart. The Arduino is then powered off the shield, as are all the sensors.

The reason to recommend the XBee connector is that incorporating remote data logging, via a Bluetooth or WiFi XBee module, becomes easy. This is especially valuable in an environment where long cables from sensor / logger location to a computer for data visualization or long term storage bears risks of damage.

Sensor shields are also available with an SD card module on board, or connectors provided for one. This again might be useful if the data logger needs to store large volumes of data locally.