I've had a DS Fatty ever since I got it in the Mario Kart pack. The only time I've ever wanted to get another was when I saw the Crimson red one which I eventually bought for the Mrs and I can't say I ever liked the build quality or buttons on the Lite.
I will eventually like to have every model of the DS just so I've got them just like I have different models of GB, GBC & GBA
Will want to get a 3DS, day one purchase in fact. Nintendo doesn't just go into stuff like this unless they are sure they can make it work. They have learnt from mistakes like Virtual Boy, which while had potential but not anything you could see unless you had the thing and also third party companies had little interest in it.
Now Nintendo are "the" name in gaming again so most companies will want to develop games for it, it sounds like a lot of devs already have devkits so that is a big plus in making sure the first years software is better than what the DS originally had...thats if they know what to do with it.