Hi Leppi,
I think you have the right idea already with the Disney sountracks.
I asked my Grade 3 daughter for some suggestions, and here is what she came up with:
*Chitty Chitty Bang Bang soundtrack
*Little Bear
*Spirit
*Charlie and the Chocolate Factory( newer version soundtrack)
*Matilda soundtrack
*Happy Feet
*Crazy Frog (I should warn you that if there is any chance these kids will play this other than through headphones, then don't buy it! I'm thinking of your sanity here!)
*Tom Chapin this guy is wonderful, and if you can get a copy of the CD "
Zag Zig" it is well worth listening to.
Another thing I thought of is putting some books on CD on their MP3 players. Just about all the best selling childrens' books are available. My children loved the "Narnia Chronicles" and "A Series of Unfortunate Events".
Here is a great site for books on CD:
AudibleHope these suggestions are useful

dg