I really think there are very few better places you could travel with a toddler than the Netherlands to be honest. Think of it: excellent public transport, all the facilities you could want and in few places will you be able to find bikes equipped with baby seats this easily - and you say you're art aficionados. Amsterdam has the Rijksmuseum, Van Gogh Museum, not to mention the superb Hermitage Amsterdam (a section of the St Petersburg Hermitage set in a stunning 17th century building on the Amstel river.) Then there's the Vondelpark, not to mention the Kröller-Muller museum in the Hoge Veluwe NP - if it's sunny when you're there, cycling around the heaths and forests is a treat and you'll have no problem if your bike has a child seat.
If you're afraid of the 'psychedelic touristy red light district/coffeeshop circuit/stoned backpackers + young kid = ???' equasion (though there's no reason to be), why not consider staying in Utrecht or Haarlem and making day trips to Amsterdam to go sight-seeing? It's very easily manageable and comfortable by train and these places are also very historic and beautiful, close by, and have the added benefit of being (to my mind) more authentically Dutch..

