This guy is the reason is the reason I haven't gotten any more work done on my Android powered rabbit.
I started off using 3 MaxBotix MB1000 sensors (downwards left, forward, downwards right). The forward sensor always worked pretty well but I had problems getting fast and accurate readings from the sensors pointing downwards. Without calibrating the sensors (making sure they were pointed away from any object) I got results that where to inaccurate to use for table top navigation.
Tonight I tried the Sharp GP2Y0D810 sensor from hobbytronics which makes a huge difference. It's lightning fast and it has a small red LED which is lit when there is an object within a 2-10 cm range which is a great help for debugging. The sensor may be less versatile then the MaxBotix sensor as it only gives a true/false result for a limited range but, in my experience, it's fast, accurate and developer friendly which I exactly what I need. It also cost a lot less :-)
The rover in the video is using two Sharp GP2Y0D810 sensors pointing downwards and a MaxBotix MB1000 for obstacle detection.