Ok, this is classic one. people, please STOP talking about an electron's orbit. Using such a language implies that we know the way an electron travels. This is NOT the case.
Secondly, you are referring to the Bohr-model of circular orbits in momentum space, not spatial space. the coordinates are not x,y,z here by the elementary quanta of the L-operator . The only "spatial" notion you can use within this context is the fact that the electron-waves must form closed standing waves along one of the circles.
Thirdly, when talking about an eletcron's position we can only talk in terms of orbitals and corresponding probabilities of finding an electron in such an orbital.
If you guys realize these common misconceptions, most of your questions will solve themselves. It is very important that you all interprete QM and its fundamental concepts in the correct manner.
Err, you guys do know that the Bohr model is hopelessly incomplete, right ?
 Check out this
Look for the QM physics section and then the Bohr model.