When my son was about 3, we bought him a train table for Christmas. It was fun to play with, but he couldn't really do much with the tracks. It was really meant to remain stationary while you drove your trains around the track so he quickly lost interest.
We had been at several other boys' houses that had Geotrax, and my son loved to put the tracks together and drive the train around. So, last year for Christmas we bought him a Geotrax set (when he was 4).
He has really loved playing with it. He started out asking us to help him build the train tracks just like the pictures that came with the set. Now, he is getting creative and building it himself in different formations. The track is pretty easy for little hands to put together and take apart. Since then, he has received some more track and trains for his birthday. Even his little 2 year old brother had to have his own train!
Geotrax is the toy that has held a 5 year old's interest for almost a whole year and counting… It's not going to be sold in a garage sale any time soon.
For more great toy ideas, visit Rocks in my Dryer.