I have 2 girls 6 and 7 yrs old and they love the crap out of some Animal crossing.
Kirby Epic Yarn too...
Epic Yarn is great for kids. Can't die and good multiplayer.
I can't quite remember what I played with when I was 7... Mostly Legos and doing drawings and such. I have vague memories of Pitfall, Paperboy, and Duck Hunt, and when I got a lil' older, Sonic the Hedgehog, General Chaos, Mutant League Hockey, Road Rash, Tetris, Rampage...
For current-gen, I hear Double Fine Happy Action Theater is great with kids, and there's always Mario Kart, Mario Party, Wii Sports, Kinect Adventures.