Originally Posted by mahasamatman
Unless it's changed recently, PADI OW and NAUI Basic are both four (4) dives. Five (5) more will get you AOW (Advanced Open Water). I did both certifications in one week (13 years ago). AOW is definitely worth it - some great diving (like Saba) requires it.
I have no idea what it is now, I don't even remember what it was when I did it three or four years ago. Night diving though which I think is one fo the things you can do with an AOW card is an incredible experience in some places - to me that alone makes it worth it.