Stop using task killer apps people!
Using a task killer destablizes your device and the apps running on it. If you randomly kill your running apps and wonder why you see weird behavior on your device you should be beaten.
With the current powerhouse devices on the market, there is no need to free memory or whatever reason you give to doing this.
If using a task killer has helped you in some way, it's only because you have one or more apps that aren't configured well (ie, sync data very often) and/or is just poorly designed and should be uninstalled. Fix the cause, not the symptom.
I currently run without a task killer on a Droid Incredible using the Seido 1750 extended battery and get equal or better battery life then I did on my iPhone. After heavy use which includes an hour of listening to music, regular to heavy web browsing, downloading at least 5 apps, refreshing Google reader and twitter feeds many times, streaming a 5 minute flash video, and other normal activities I made it the entire day with over 40% of my battery left at the end. (If your aren't seeing this type of battery performance, see my previous post on fixing your battery problem)
Bottom line, please stop using these task killer apps and let the Android system do what it was intended to do. Otherwise you just give the Android platform a bad name.