Well I'm staying off the online 'bullcorn' because I think you should know well enough what classic system games blow and not once you see the list.
Far as on the system goes for the kid I'd look into anything with Spongebob or Cars as they were done well by THQ. Elebits is good for anyone. Kids also like the little things in Wii Play, plus you'll need 2 controllers really anyways so it's just $10 for all those cheap quicky fun things of which 1/2 are pretty good. I'd also recommend Super Paper Mario for a mix of SMB classic with some Paper Mario rpg elements and tons of story tossed in. Mario Party I understand was the first good one since like the original 1 or 2 so that's a good idea. On the older end of things CoD3 is damn fine, but MOH Heroes 2 really 'uses' the system, has ea nation online (no gay codes), runs like a champ. Metroid depending how you are on kids playing is good, and at the least for you too (and MOH is its equal too, EA did a great job.) If you don't mind an older game brought back, Godfather is seriously impressive with the wii controller as those 3rd person 3D worlds actually are navigatable, aimable, and drivable in a good way finally, camera too.
Honestly I'd stay away from Zelda unless you can dedicate a good 2 hours a shot at playing it because it still uses that archaic save system the 2D went by, and if you don't hit a spot you're sent WAAAAAY back like a good 10-20 min or worse at times as the game is huge and with the loss of some things. Total horseshit, plus the primary attack is just wagging the controller which sucks as the secondary like bow and arrow is perfect, simulating like a real bow would work...go fig on that tardation. It's overrated basically...I'd call it the Wii's FF7.