One of the coolest features of a rooted G1 is the ability to manually close an application as you see fit. But with the release of Android 1.5 - better known as Cupcake - comes an application that allows all end users better control over their programs.
While the control isn't absolute, the power is. You don't use CE2 to individually shut down badly behaving applications. It's basically all or nothing, except that you can set exclusion rules for certain apps you want to be left alone. I've found this option redundant for myself because a running service will restart the essentials - such as my home replacement.
Close Everything 2 is the latest version of a program by the same name - which I never tested out before getting Cupcake. I read some forum posts about people getting mixed results, and I wasn't too interested. V.1's Market description states that it "tries" to close programs. Regardless of the accuracy of negative reports regarding v.1, I can tell you that version 2 works perfectly. It has saved me from a reboot on more than one occasion.
It's great for those with un-rooted phones, or those who do have rooted devices but don't want to shut apps down one-by-one with Advanced Task Manager.
V.1 is free and works on pre-Cupcake Android phones.
V.2 is for Cupcake and above, and costs £0.85, which currently works out to $1.30.