Razor-qt is an advanced, easy-to-use, and fast desktop environment, which is, like KDE, based on Qt technologies. It has been tailored for users who value simplicity, speed, an intuitive interface and high customizability, therefore it features only few basic components, while most applications, like a File-Manager, have to be added by the user. Due to this, Razor-QT runs fine on weak machines, too.
Razor-QT has no WM of it's own, but it will run with most Window Managers, while KWin and Openbox are the common choice - you can change it either through Razor's Session Management tool, or by editing ~/.razor/session.conf.
In order to use Compiz as Razor's Window Manager, you have to edit your session.conf like this:
[General] windowmanager=compiz ccp
Methods like fusion-icon, adding compiz to the .xinitrc or compiz --replace ccp & will usually result in crashing X.
A fresh Razor-QT won't provide much of the tools you need, as it leaves to the user, what to add. A collection on useful apps (which use QT) are found on the projects homepage at  Another source for, especially lightweight, apps is Lightweight Applications.