Sturdy DS Case - Recommended!
The "Nintendo DS Mini Folio" is a very sturdy case that perfectly fits the DS Lite, stylus, and 4 games or so.

The case is fairly thick and can stand on any side except the "spine".

The included metal clip is very strong and can be used for attaching the case to a backpack or belt loop.

The overall construction is very solid and does provide a good bit of protection for the DS.

Recommended!

Decent
This is a decent case for the price. The DS fits nicely, though I wish the elastic band holding it in place was a little tighter. There is dedicated for storing games, but there is a mesh pocket that can hold a variety of things, including about 4 games (stacked). The outside material seems very durable, as does the zipper. Overall, the case is worth the price.

Compact Case for DS Lite
I was looking for a small case for my Nintendo DS Lite, because I prefer to put it inside a purse or backpack. I wanted something compact and easy to pack, rather than something with lots of storage space, its own handles and straps, etc. Basically, I just wanted a protective case rather than a standalone gaming bag.

This case is almost the perfect size for this. It fits the DS Lite comfortably without leaving too much wasted extra space, and the case is very compact. When closed, it actually resembles a small hard drive (but with a cloth cover), and it's thick enough to stand on end, making it convenient for storing the DS Lite on a bookshelf, etc.

The front flap of the folio has a small mesh pocket that can hold DS games. Although the pocket mesh stretches a bit, it has a velcro fastening that's difficult to close if you keep the games in a plastic game case. With the DS Lite inside, there's enough room inside the case for the game protectors, but the pocket design makes it a bit harder to squeeze them in.

My only slight negative is that there is absolutely no place to store the charger. Presumably the larger original DS would fill all of the interior space, but with the DS Lite, there's a small bit of space at the ends of the case. If the case was just an inch longer, there may have been room at one end to squeeze in the charger.