Mallorca. Go to Pollenca in the north (the old town, not Puerto Pollenca, which is great for a day trip to the beach but not as nice to stay in). Gorgeous restaurants, friendly locals, very child friendly. Fly to Palma and hire a car then hire a villa. The weather will be lovely and you'll have a great time. Fly on Saturday then go to the market in the town square on Sunday (it's only there on Sundays) and stock up on gorgeous fruit, veg, cheese, ham...it's a lovely place.