I consider the later years of the N64 and early years of the GCN to be home to the majority of Nintendo's best games, so, yeah... I have some fond memories with the GCN. Overall I call it my favorite console.
The GCN had games that kept me playing on years for end, like Animal Crossing and Super Smash Bros. Melee. Maybe it was just a matter of my age. But the fact of the matter is that no game has entertained me anywhere near that much after that.
The GCN also boasted impressive sequels to single-player games that I also loved, such as Paper Mario The Thousand Year Door, Super Mario Sunshine, and Twilight Princess. All three of those franchises going downhill ever since, sadly. Of course, Paper Mario going down the most, and Zelda the least.
There were games that disappointed me, like Mario Kart Double Dash!! and The Wind Waker. However, my disappointment with those games wasn't even tangible, like it is with Nintendo's Wii/3DS/Wii U sequels. So I won't even count those as disappointments anymore. Although I wouldn't be hyped to see direct sequels of either of those titles, I can't lie.