beautiful place although spoiled by tourism already. still if you get off the main track you can find some nice, almost untouched places and people.
bike is a must in Bagan! you can rent it practically everywhere and it gives complerte flexibility - plus you can visit places no one normally would take you to.
my favorite area was south from Nyaung U - more quite, with quite nice temples. it's best to actually spend nights not in the middle of Nyaung U but more to the east - it's closer to temples area and give great opportunity to catch couple sunsets and sunrises. i've chosen winner guesthouse, on the road to old bagan - quite nice, friendly, clean place, with aircondition and breakfast.