I've done a lot of travelling and was a travel agent for a while too. I've been to The Whitsundays, Fiji and Vanuatu I'd recommend Fiji over Vanuatu any day. We stayed at an all inclusive resort in Vanuatu for 5 days in January 2009. It was great value and the food was fantastic but both DH and I personally think Fiji is nicer (although they are both beautiful places) but the Fijians are definitely more friendly. Neither are that expensive to be honest, especially if you book an all inclusive resort. You would save on airfares though if you stayed in Australia.

Club Med's get a really good rep for keeping families happy and busy but the last I heard and read about Club Med Lindeman, it was a bit old and tired. Check out a few travel forums for recent feedback. I often use the Trip Advisor website - it has up to date reviews and lots of good info.

DH's sister is a travel agent at Flight Centre, has been for 11 years. She went to Club Med Cherating Beach (Malaysia) last year with work and loved it. She has done A LOT of travel over the years and knows the industry so I highly regard her feedback.

I hope that helps! Have fun planning!