We got the cat in numberland from the library too; ds8 has always enjoyed discussions of infinity, probability, estimating and collecting 'stats'; I think maybe more of the 'messy' stuff people have mentioned.
At 6 he came up with a game for the car where we'd count types of cars in different areas of the city and talk about why the numbers were the way they were and other variations on this.
I don't think he's driven to count, but he enjoys it.

Has anyone checked out The Number Devil?? Very awesome.
DS enjoyed this one as a bedtime story a couple years back; might have to try and find it again (libary).

http://www.amazon.com/Number-Devil-Mathematical-Adventure/dp/0805062998

Kriston, that is wonderful, if not entirely unexpected news, about your ds4! Very cool. Do you think the glasses are helping in this arena? If so, good investigating, Mom! smile