I have the Metroid Prime Hunters: First Hunt demo. The controls are great, but it just isn't my kind of game, really. It's more a shooter then a 'real' Metroid (do note that I love 'real' Metroid games).
Animal Crossing is perfect for me though. I'm in a train for 1.5 hours a day to get from and to University, and AC is one of those games you play for half an hour then quit. Add a lengthy game (Advance Wars, Golden Sun, Pokemon) to you GBA slot, and you're good to go ;-)
And even if it weren't for that, I'd still play it a lot. I played the cube version a lot too. But I guess it's just one of those games you have to like :-)