When I switched to Go Launcher I noticed an increase in battery life (decrease in drain) over Sense (Rosie).
I do not use many widgets, so that might be a significant difference. I have always found the biggest difference to be in the apps loaded on my phone.
Given a static set of apps and a routine movement with in your coverage area the screen seems to be the big drain. My 3VO seems to handle deep sleep well, even with all radios on. The huge draw on battery seems to be screen on conditions. How long the phone lasts on a charge has a strong correlation to how long the screen is on.
My Triumph was terrible with any of the radios on, it just didn't go into deep sleep.
I have sworn by Battery Mix for the tools to track down battery draining apps. Better Battery Stats is also an excellent tool, but less intuitive.