Yes, GBA has one more holiday left in it. The sales will be a lot lower, but it'll still be going.
I think New Super Mario Bros was a big deal for North America. My cousin's boyfriend couldn't stop playing it when we were hanging out at my grandparents' place this summer. It sold him on the DS. I have a feeling that we're also seeing the sum of many important games like Animal Crossing, Nintendogs, Brain Training, Mario Kart, Tetris and Metroid adding up. It's possible that DS Lite took off not just because it was nicer than DS, but also because people were already interested but heard a new version was coming out, so they waited.
Some life to date sales for Brain Training, Animal Crossing and Tetris would be really interesting. I know Nintendogs is huge, and I can assume the Mario games have done well, but I wonder about those ones?