Pokemon is still a good bet or any of the film related ones Finding Nemo etc - sorry Jenky but I would have thought that the Zelda series might be a bit challenging for that age
Wario Inc. Brilliant games with about 200 different levels all palyable with one button. Sounds odd but seriously addictive, not violent, and will last a 7 year old for ages.
i cant give any game names but, if you go into a shop like game or argos they will recamend you some. very usuful. and then you can choose the one that he will like the most. does he like action or adventrue that sort of thing. hope this helps!