Australia, mainly for seeing all the wildlife.
Flew into Sydney and saw the sights there, breakfast with the koalas, then drove up to Port Stephens, did a boat trip where we saw about 150 whales and dolphins. Flew up to Cairns and from there went on a small boat to Great Barrier Reef, did scuba diving and snorkelling and saw reef, giant turtles etc. Then also went to Atherton Tablelands and stayed at Lumholtz Lodge with a lady who rescues tree kangaroos etc and got to see / feed some possum, pademelon, bettong, saw tree kangaroos, went on trip and saw platypus. Then stayed in a treehouse in the rainforest an hour from there and saw wallabies, possum came to the door, also cassowary came just under treehouse. Drove along coast to Daintree rainforest and went to Kuranda, saw crocodiles in the river, beautiful beaches, rainforest etc. Then flew back Cairns to Sydney and saw kangaroos in the Blue Mountains.
Within Europe it would be Lapland over Christmas time which was magical with the children.
Within UK Isles of Scilly, we stayed on Tresco, kids loved flying in on helicopter and out on small plane and the wildlife, canoeing around islands etc.
I think next year it will depend where you can go and also will depend on your interests, budget, time available, season, age of any children etc. There are lots of lovely places to see around the world.