This. Nowadays I just use Zukitre for GTK/Qt and the Tango icon theme, it suits TWM/CWM and any other minimal WM without tons of effort. A dull gray theme combines with everything, even with my Cyan titlebars for TWM (they make a great contrast with red borders and wheat yellow icons/menus). You know, I want to use my computers and the titlebars stand out like crazy. And, actually, I've just borrowed an old color config used from a university.

The background?

       xsetroot -solid gray20

I never understood the trend on dark/bright modes; the gray themes from my childhood/early teens with W98SE (and used by Mac OS 7/8 too) are just neutral and barely 'sit there'.