Scuba diving in Asia forum

hi, i am thinking of getting my padi license this december, probably up to deep ocean (or whatever makes you dive deep and at night).
i've been to thailand twice so far, been to phuket, koh tao and phiphi. and i tried scuba diving in Koh phi phi, and snorkeling in other islands.
and now i am trying to plan two-weeks scuba trip to thailand.
so please tell me where i should go to get my license.
Things that i'm condering are:
1. price for course and lodging (i think all PADI courses cost the same, am i right?)
2. sites and water condition (if i remember correctly, rain hits east in
winter and west in summer.)
3. surrouding islands (i'd like to check out other surrounding islands as well.)
4. new place (i'd rather go to a place i haven't been to)

Please share your experinces and experties!