Nell, if you liked Croatia then you should pay a visit to Slovenia. There are nice resorts and also a lot of sights nearby.
Clare72, if you fly into Split you can wander along and find a place that suits, going directly with a package to a resort you're limited and the other way you get a nice taste. Hire a car and move north to the less populated spots, or less expensive, it'll save you cash and also you could end up in somewhere like zaboric where you can have a beach all to yourself! (We taught our little one to swim there last year, so clean and safe)