After a quick day in Rangiroa, we headed north to another atoll called Fakarava.  There isn't much to see on land here, as its just a narrow ring of sand and palm trees surrounding a huge lagoon, but the diving was incredible.  We booked two dives and everything we read said that the diving here would be very similar to the diving in Rangiroa.  Other than the unbelievably clear, 80 degree water, we found it to be a completely different experience.