I have a
Scanguage ll which is really good, it you can find the hex codes you can make custom gauges or read OBD outputs that are vehicle specific.
I also have an early model
Autotap which is good but no longer supported..
Last in my bag of gadgets is an OBD/Bluetooth dongle, and app for my Droid called "Torque" (free). The dongle cost $17 on Amazon and works flawlessly handshakes every time with my Droid.. Can reset codes etc... not sure if it is capable of reading vehicle specific codes, or just generic codes..