Open Source Data Logger Project Using the Arduino?

I was thinking of developing a general purpose sensor interface peripheral
for my ZB1 board (Loading...). The new board would consist of
four channels of instrument amps or op-amps. I would include a reference,
a negative 5V supply and a little prototyping area. The datasheet
would include a detailed op-amp tutorial.

Since the ZB1 can be connected to a backplane other peripherals like an
SD card could easily be added. Also the ZB1 has an XBee so remote logging
is possible.

I would be interested to hear what types of sensors people use and what difficulties
were encountered.

(* jcl *)