Of course the Android Market is riddled with all sorts of task managers and task killers, but none of them beat the one that Samsung includes with the Galaxy Tab. Even though I am not the biggest fan of the TouchWiz interface, this feature has kept me from switching to another launcher.
Android devices support multitasking and while that is an amazing feature, it can bog down your system unnecessarily. I know that I hardly ever need five applications open at the same time. The 1 GHz processor and 512 MB of RAM can not handle too many invasive applications at once. So what do you do? Use the Task Manager of course!
It is always readily available. The quickest way to access it is by longpressing on the home button to bring up your recent apps. Under them you will see a button that says Task Manger. Tap it and you are in.
Once in, it will show you your running applications and how much RAM and CPU they are taking up. You can quit out specific apps by clicking the Exit button to the right of the respective application, or you can exit them all at once by pressing Exit All in the top right.
That is not always enough for me though, so I like to switch over to the RAM tab at the top of the app. If its over 300 MB I know that I can usually clear up some of the RAM, so I press the Clear Memory button and closes some more background processes.
The absolute best feature of the built in Task Manager is the widget. It will always show you the active number of applications open at one time, so you know if something is open in the background that you do not need. Tapping on the widget brings you back to the Running Applications page and you can manage them as described above.
Do you use the Task Manager?