I got the DS about a year ago, and I still have it and it is working perfectly fine. The first thing I noticed about the DS was how expensive the games were. They cst $20-40 a piece, a price that I thought was not worth one little game. Nevetheless, I bought a few and were surprised about how bad some of the graphics were. Some of them were perfectly fine, but others were not as great. I actually thought that the DS was a waste of money because I had to buy all these games, but in the end, it worked out ok. I guess the gameplay of the games were ok becuase most of them utilized the touchscreen and the buttons in a positive way for thier games. The mic was also cool to play with too because in one game, nintendogs, you could speak into the mic and whatever you say will be known. I also like the games selection. There were many games to choose from and each of them had something different in them. When I went into the store, i was surprised about how many games there were that were made specifically for the DS. Too bad there was no super smash for the DS :(.
The sound and graphics quality of the DS itself was ok for a screen that small. you could not really tell the difference between ppixels that easily and the graphics were smooth. You could also close the DS so that both of the screen flaps closed and became one like modern day cell phones or something. It was easy to store. Too bad the DS wasn't designed to hold music or videos becuase if it was, that would be great. The price I got it for was ok, but I have to tell you this. It was a bit pricey for its qualities and games. I didn't feel like it was really worth 125 dollars. As you all know, Nintendo has madfe another Ds called the DSi. It has a camera and many new features that the old DS didn't have. If you wanted to save money on a DS and buy the regular DS, don't. The DSi plus the new features are way more valued than the DS. Just try and save a few more dollars. Did I mention that it has a cool camera? Well anyways, the DS was an ok experience for me.
Update On May 06, 2010: What was sometimes bothering me abut the ds was that there were some games that you had push the buttons as well as use the touchscreen at the same time. Sometimes it was hard to manage as you needed a stylus for the touchscreen but you are pushing the buttons. Sometimes though, it actually made it more fun to do.