I stay in Rayong for work, and school for for my son. My missus has a business here also. When I retire in a few years I've mulled moving to other parts of the country, but not sure if I'd want to live there permanently. (Rayong is close enough to Pattaya and U-Tapao airport for travel, shopping, etc.).
Chiang Mai is a favorite place to stay and we have friends there, but don't want to be there during the 'burning season' for example.
One of the good things about Thailand is the cheap internal transport, domestic flights and accommodation available here. You can travel around and scout out places to live, or vacation, even on a tight budget.