My Nintendo DS
The first thing people would notice about the DS is that it looks like a bigger, fatter version of the old "Game and Watch" handheld games produced by Nintendo. In my opinion, the Nintendo DS' most striking feature would be it's dual screen. Both screens display graphics but the bottom screen is touch sensitive. Technical details aside (both screens have their own ARM processor), the utilization of the screens would generally depend on the game you are playing.
Games like Brain Age and Animal Crossing would require you to utilize the touch sensitivity of the bottom screen although it is not as intensive when you are playing the latter. Games like Mario Kart DS almost don't require you from touching the screen.
Dual screens aside, the DS' exterior has the prerequisite directional pad and four buttons, 2 trigger buttons, old-school volume control, built-in microphone, ports for headphones, mic, a Nintendo DS cartridge slot and a GBA slot. Under its rather solid appearance, the DS is WiFi equipped for both multiplayer with one or more DS units in a local area or over the Internet.
I've got asked quite a number of times on why I bought the DS instead of the DS Lite. Well, the DS is certainly cheaper and sturdier compared to the DS Lite and it is very much not a fingerprint magnet. It is pretty much a bargain for such a cool gaming device.