Lavender. It's dull, unappealing and doesn't excite me one bit about the spike damage I've just dealt or the awesome item I just received. I'm going to cite FFXI in regard to this, because the standard bright green on yellow text just got me excited about even the most common of treasures:

You find a beastman's seal on the wild rabbit.
You find a beastman's seal on the wild rabbit.

Now, can anyone see what I'm talking about? No jokes about the stark yellow text on the light background, please! :P