First up is Tomy's Q-Steer which is an RF controlled micro car. It is Tomy's replacement of the immensely fast and very hard to control Digi-Q as seen here:
The Digi-Q is very hard to find nowadays, and if you have one (like me) then consider yourself lucky! Even Amazon.com deosn't have any: http://www.amazon.com/exec/obidos/tg/detail/-/B0000DIT4R?v=glancehttp://www.microrccenter.com/ has an overview of some of the Micro RC cars on the market. You can read about the new Q-Steer on Gizmodo.net Q-Steer's official page can be found here.
If cars are not the thing for you, then try tanks! Look at this:
I've had a set of 4 tanks for more than 6 years now and they still work... They are too much fun as you can fight 2 vs 2 or each one on his/her own. Look at this video. Also, make sure you visit Dan's Data for a more in depth look at the tanks.If all that doesn't apeal to you the try the trains:
If you are into F1 racing then this is for you:
You can purchase them on ebay.Last but not least, I leave you with two links: The google tanslated Takara Tomy blog so you can keep up to date with japanese toys. and the Takara-usa.com site for more toy ideas for young ones.