Seems that my choice is somewhat at odds with most here. But then I work almost exclusively in Windows using Tk. After trying many alternatives I finally settled on ActiveState's Komodo and their companion PDK. Although in the past I have used Eclipse, I found it became very slow when handling large files. Komodo remains responsive and allows me to bundle everything I use into one place - particualrly as I package applications with PerlApp and use PerlTray to create tray apps.
As for secret weapon? Nope, just what works!