We've just had the most wonderful week - we couldn't recommend Fiji highly enough. We stayed at Fiji Beach Resort and Spa (run by Hilton) which was completely family friendly and had a lovely relaxed vibe. The rooms were very stylish (think modern free-standing baths, coffee machines and spacious tropical rooms decorated in cool neutrals) and staff incredibly helpful and friendly. There were loads of activities such as fish feeding, tug of war, coconut demonstrations, and beach games which the kids could join in as they wished without having to be signed into a kids club (although this was also an option). The food was fantastic, the spa was delightful and the sunsets at "Happy Hour" were just magical.
Sketching on the balcony after lunch...