Vida DiCE is great for the professional, but often complicated for the DIY home mechanic to install. iCarsoft i906 unit is one of the best scanners that money can buy. It can read and data log just about everything on the car. This device can even clear and reset SRS warning messages, which only a dealer would otherwise be able to do.
If you own a Volvo or a Saab, this is a must have tool to keep in your glove box.