Don't use task killers at all. If you paid for it, try to get your $.$$ back. I was all over atk's and hatting how apps auto started fresh from wm to android. Got to the point everytime i woke phone it was like turning on, waiting for home screen to load. I am rooted so my battery was lasting longer than stock 4 hours, but after i decided to stop the auto kill and see what happens for a couple days, i quit using, un-installed the task killer and haven't ran one in last 3 months +. if you are worried run
http://market.android.com/search?q=p...t.watchdoglite (click link using phone) it lets you know when apps get out of control and you can then kill them. But ATK's kill your phone usability and battery.