Lots of ideas back here. On our bike there was a little paint in the BB housing. This caused a squeak at 12000 miles.
I know a guy who's similar squeak turned out to be a broken frame (carbon fiber-single bike), but I really doubt that's your problem!
I've never used teflon tape. I prefer a LIGHT coating of anti-seize, but a light coating of grease is easier to work with.
Bushnell has an article on the list of things to grease to eliminate noises.