I like the Carpenter's Wheel (Star). Simple, but impressive great in three colors.

Day and night - Elinore Burns

Another option is using many shades of those 3 colors. I just finished a quilt using the Scrambled D9P. It's so fast and easy to put the top together and a lot of fun when you go scrappy with lots of shades.
My grandson asked for black, gray and green. Here is his quilt and he totally loved it!![ATTACH=CONFIG]392094[/ATTACH]

Disappearing nine patch would be my choice.

Thanks to everyone for all the wonderful ideas for my three color quilt! Your ideas have definitely inspired me!