I love the color combos, but I think brown is one of those colors that is too hard to spot and just blends in a little. I thought the most successful color day (well, that I was there) this year was the pink shirts. I was spotting everyone left and right. Well, it felt that way, lol. I'm sure the lime green was easy to spot as well but I wasn't there Thursday. The purple would have been so, so, so much better had it not been for the fact it seemed to be the choice color of the day for everyone, lol.
Or teal with the chocolate/brown

I'll make campaign buttons for teal shirts if I have to!