Wirelessly posted (Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/530.17 (KHTML, like Gecko) Version/4.0 Safari/530.17)
For anyone still having this issue, here's what I did to FIX it permanently for me.
In System Prefs, go to Network. In the sidebar of available network devices, highlight and REMOVE "Bluetooth".
Reboot and you're good to go. There's something with Bluetooth available as a network device that causes the dropout of devices (mice, headsets, keyboards).
I did this AGES ago and haven't had a problem since.