I used to play Pokemon FireRed for some time. Nowadays I prefer Super Mario Bros, we can get so competitive as a family.
I like the N64 Legend of Zelda games and Windwaker, Skyward Sword was ok, but I found far to difficult. Oh, and Super Mario Galaxy(the first, second was pretty bad in my opinion)
Probably the Legend of Zelda games with Twilight Princess being my favorite in the series. Metroid is probably my 2nd favorite. I thought the prime games were good but they weren't my favorite. I loved Super Metroid and Metroid Fusion though.
Pokemon is the one i have put most hours into. Alwasy remember the days of pokemon gold. That was my childhood that game. Was a big fan of mario growing up as well.
I'm going to have to go with New Super Mario Bros. for Nintendo DS. I have yet to play another Nintendo game that has had as large of an impact on me. A close second would be Paper Mario and the Thousand Year Door for GameCube.