Sysinfo is both an app and a widget. The app gives pretty detailed info about the Android device, and the widget, which is 1x1, gives up to 4 different stats like memory, SD card, cache, and battery.
The app could be designed with a bit more eye candy. As is, it's really plain Jane. The widget isn't much better, pure text, not even bar graphs.
Still, it is free, and that must account for something.
Rating: Try it