I've released "Plastik", a Snow Leopard-only traffic lights pack.
For Snow Leopard (including dark-window apps like QuickTime, Pixelmator and FaceTime): http://fav.me/d4hdkij
For iTunes: http://fav.me/d4hgfx9
Also, I've updated my Lion traffic lights for Snow Leopard, now with iTunes compatibility!
Go get 'em now: http://fav.me/d3hsv1w