So we are going to Van Gogh museum for free (savings of almost 60 euros – yes!) and we could go to Rijksmuseum (I am tempted by Rembrandt, but 2 museums in 2 days might be too much for us).
Other things not to miss:
Floating flower market
Red lights district
Royal Palace (not the inside I guess)
I am not sure about canal tour on boat… Is it something to consider?