I think it would be useful to present information about different types of cars/vehicles. Subjects could include:
-- family-friendly features
-- car seat compatibility
-- roominess of the front seats with car/infant seats in place
-- roominess of the 2nd and 3rd row seats
-- roominess/usability of the cargo area
-- recommendations for leather vs. cloth
-- safety features
-- gas mileage
-- etc
It might be hard to keep up-to-date on this for new additions of the book, but I think it would make a great category for board posts.