I just installed Ubuntu on my laptop (Core 2 Duo Sony Vaio) and am having a problem with the external keyboard and mouse. When I first logged in the left mouse button does not work, this can be solved by unplugging the external keyboard/mouse's USB connector and then plugging it back in again. But Then randomly other problems happen. (Shift gets stuck, keys don't work etc) The keyboard and mouse are a generic brand wireless (A4 Tech) that I got for cheap. Both work OK under windows so this is a major pain.
I've witnessed a similar problem from a customer a few weeks ago. It appears that the version of bluez shipped with Ubuntu 10.10 is buggy and can lead to that kind of frustrating behaviour. You may want to upgrade to the latest version of bluez. There is a ppa for that here.