Damn this is old but I have to refuse you guys:
juice defender is not actually a task killer, it just disable the radio of the phone and periodically activate it to let the phone sync the apps like mail, facebook, and those kind of push notifications.
So, to everyone who read this, it really works, but unfortunately not for everyone.
Edit: It works for me, it works really good.
Well that's all
I have the ultimate version of juice defender. And it works almost perfect for me, other than a few minor glitches. Without it I get maybe 7 hours out of my fascinate with it just sitting there. The 3G network drains my battery very fast, with apps syncing at different intervals. Which causes the 3G to be connected all the time.
But with Juice Defender installed and setup properly. I get at least 2 - 2.5 times more time from my battery. It doesn't kill any apps. What it does is disable your 3G and wifi connections. Then depending on your settings it allows your apps to sync up every so often.
The ultimate version was worth the $$$. Since it allowed me to fine tune my settings