I purchased a Trail Tech Vapor enduro computer for my '03 EC300. The install was relatively easy, and calibration took nothing more than a ride with a GPS (and some simple math as described in the manual).
It is an amazing piece of equipment, and has survived the beatings I give my bike without complaint or problem. It displays a tach (bar graph and digital readout), radiator fluid temp, ambient air temp, speed (corrected via GPS if you have one), and accumulates engine run time.
It has trip meters, such as trip distance and time, as well as peak speed and RPM for the trip. The only downside is the inability to adjust the trip odometer, only to reset it.
Overall, the folks at Trail Tech were helpful in placing the order, and they make a product that's worth every penny.
Photos:
http://mercury.pr.erau.edu/~marti1e8/photo_vapor.htm