I use Quick Settings (free from the market) to turn different things on and off as I need them.
I also use Task Panel lite (with it's AutoKill widget) to kill off processes. I know that dormant apps don't use processing power, but I figure that having them in memory MUST drain some power, so there's no harm in killing the ones I don't want.
By doing things this way I've gone form losing around 30% power overnight to losing less than 5%. Last night my battery was at 52% at 1am, and today at nearly 6pm I've got 37%. Today I've received calls and texts, and received emails and used the Market on wireless. And I have Bluetooth on when I'm in my car (about one hour per day).
On that basis, I'm pretty happy with the battery. However, if I leave 3G on, allow auto-updates for Google Sync (contacts and calendar), and let Twitter and facebook update regularly in Timescape, my battery dies MUCH quicker.