Thinking of moving to Queensland, seeking family friendly with coastal/laid back lifestyle.

Looking to make the big move with 3 pre-school aged children next year. While we're prepared to live in Brisbane, we'd really prefer either on the coast or something family friendly with laid back 'sunny'/pool/beach lifestyle - after all, that's why we're moving. Are there any non-suburby suburbs in Brisbane? Or should we look to Sunshine Coast? Would prefer not too great a commute for work, but happy with up to 30-40 minutes travel whether by train or car.
Keen for current suburb and school suggestions anywhere - we'd be looking for eventually buying in the no more than 550K range. :)