I am running Windows 7 with Aero enabled and everything about my theme unchanged. I have tried various ways of adjusting colors and translucency, but I can't seem to find a way to make the active window's titlebar more distinctive (compared with the inactive windows).
I don't mind registry or manual theme hacking (if someone can explain what I need to do), but I can't go downloading arbitrary software on to my machine.
Here is a screenshot of two windows, the one on the left being the active window:

Ideas?

