Get this Digital Clock Wallpaper, which is always showing the current time. You can activate or deactivate the seconds in the settings of the wallpaper. You can also set different background colors.
Note: It is live wallpaper so you can't open the app, you will need to follow the instruction in order to set the wallpaper.
Instruction:
Home -> Menu -> Wallpapers -> Live Wallpapers
This wallpaper is completely free and without advertisement!