I am using a Laptop Lenovo x121e (AMD-Version). The laptop has a Synaptics touchpad/trackpoint combination. The touchpad is very "jumpy" when trying to tap the pad for a mouse click.
Normal mouse movement is fine but when I try to tap the touchpad the pointer often moves away a few dots. Similar behaviour has been reported by windows-users of the x121e, here a solution is to install the latest driver from Synaptics. I haven't found a similar solution for Ubuntu (11.04, 64 bit).