The last time I did a complementary color scheme kind of thing on the walls I simply cheated and got some paint chips, the ones that have 6 or 8 similar colors on one piece of paper, just flipped through some until I found one that felt the most comfortable, then selected several cans from the same sheet.  That way the colors were guaranteed to not fight with each other, there was a bit of difference but it didn't scream at me.

Those coffee colors were exactly what I selected, and I am more than pleased with them.  The walls just hug you!  The ceilings are stark white, but they will probably end up a very light coffee color eventually.  Or not.  They are kind of like whipped cream on the coffee!  Most of the walls are the lightest, creamiest coffee, with accent walls here and there of the darker colors.  Visually, it is all tied together and you don't consciously see the variations in the color unless you look closely, but it causes the eye to move and not see just boring walls.