Dead pixels are a fact of life on LCDs, just like questionable geometry was always an issue with CRTs. I have a dead pixel on my GBA but never once thought to return it since I know that the problem exists with the screen. Thankfully things have improved over time to the point where dead pixels are rare.
My current laptop has no dead pixels but my older laptop, which is nine years old, has two. They were there from the day I bought it brand new in 2000. However, it was a huge improvement over the days of old--my 1993 model PowerBook has five. My old Macintosh Classic may not have dead pixels even after nearly two decades, but CRTs have their own problems--I had to manually adjust the focus on it after about 13 years since it had come out of focus over time. (It still looks good, I must add--the machine works great and actually gets used now and then).
I remember when the old PowerBooks first came out. Apple had a policy where you needed to have something like eight dead pixels to even consider replacement. I'd imagine there is still a similar policy in place not only at Apple, but also at Nintendo, Dell, IBM, Sony, etc.
I'm going to say the DS is not a toy either. I'd classify it as a handheld electronic device much like the iPod Touch, except that its primary purpose is to play games, not music or videos.
Also, if there is a post that you can't delete, my recommended solution is to edit it and write <<erroneous post, please ignore>>.