With the imminent release of Lion, perhaps it's time to clear out all those apps you don't need anymore. AppTrap is an app up to the task, which integrates nicely into the OS X way of uninstalling apps.
We all know that the Mac way of uninstalling apps is just to delete them. The size of the preference files, settings and other cruft left behind is so small in comparison to modern disk sizes that you shouldn't have to worry about them. But what happens when you want to clear out your hard drive properly after each uninstall? Installed as a Preference Pane, AppTrap runs in the background watching for when you trash an application from your Applications folder. It will then locate any files associated with that application and ask you whether you want to trash them as well, removing the need for you to hunt them down manually.
Other uninstaller apps that we've featured on the Daily Mac App before primarily work along the Windows way of uninstalling. Select the app you want to uninstall from a list of installed programs and hit delete. But AppTrap enables you to continue deleting apps the way Apple wants you to, without leaving all that cruft behind. It's fast, effective and free.
If you install and delete loads of apps the Apple way, then the free AppTrap is a must. It's downloadable from the developer's site and supports Snow Leopard and the soon to be released Lion.
Thanks to hispidignoramus for the suggestion.