For a while I've been kind of on the fence about task killers. I have been using Advanced Task Killer (ATK) and while it does do the job of killing tasks, there is lack of evidence that it actually saves battery, and it does cause problems for some people. I did some googling and I am currently trying out the "Task Panel Xtra" app. It only kills stuff that you specifically put on its kill list but is otherwise similar to ATK. Again, I am not looking to save battery juice by this. I think android does a fine job. I wanted to post this in the "top 5 apps" thread but it is really only one app, and the whole task killing thing kinda stands out on its own. For battery saving I thought I'd try Juice Defender. Seems to have good reviews and lots of custom/advanced options to play with.