Ubuntu Tweak, it's the one which you should install first. Ubuntu Tweak comes handy in easily managing and tweaking the settings of an Ubuntu system. It allows you to install and uninstall applications, choose display settings and manage your desktop settings, among others. It can also be used too install a large number of application (including some of the above listed ones) easily using the graphical interface. It also includes Compiz Settings Manager. The best feature I found is the Package Cleaner with the following options available till date:
Go to Ubuntu Tweak's Download Page and use any one of the listed methods for installing the tool. I would suggest you follow the link to download the latest .deb package and run it on your system. The menu item comes under Applications -> System Tools -> Ubuntu Tweak.
- Clean Packages
- Clean Cache
- Clean Config
- Clean Kernels
Go to Ubuntu Tweak's Download Page and use any one of the listed methods for installing the tool. I would suggest you follow the link to download the latest .deb package and run it on your system. The menu item comes under Applications -> System Tools -> Ubuntu Tweak.
Here are some screenshots:


