there is an interesting machlokes in Bava Basra.
one shita is to daven towards the Bais HaMikdosh. this is the Halacha.
one shita is to daven towards the west, wherever you are (because the Schechinah is in the west)
one shita is to daven towards the east, wherever you are (because the Schechinah is in the east)
one shita is to daven anywhere (because the Schechina is everywhere)
Rav Sheishes would daven anywhere except east (because certain avodah Zarah would daven east)