Bind keys to actions in KDE 4

The following definitely work:

1. For Launcher using Win Key Install ksuperkey:

   sudo apt-get install git gcc make libx11-dev libxtst-dev pkg-config
   

   Make sure that the keyboard shortcut for your application launcher is set to Alt+F1 (this is what ksuperkey will send when you press and release the Super key on its alone). Right click on the application launcher icon → Application Launcher Settings → Keyboard Shortcut. Assign Alt+F1 shortcut for the launcher over there. Then run the following commands in a terminal:

   git clone https://github.com/hanschen/ksuperkey.git
   cd ksuperkey
   make
   ./ksuperkey
   

   Make sure to check that your meta/Win key now serves your purpose. Now you have to set ksuperkey to Autostart, for example in System Settings → Startup and Shutdown → Autostart → Add Program… → small Browse button → Select the ksuperkey application, and you are done.

2. The default shortcut for the System monitor is Ctrl + Esc, you can override this if you want, go to Global Shortcut Settings -> run Command Interface (in KDE component) -> System Activity Change the shortcut over there.

3. Go to Global Shortcut Settings -> KWin (in KDE Component) -> Show Desktop Create shortcut of Win+D.

4. For Nautilius or Dolphin, Use this link to associate apps with shortcuts
   Shortcuts and transparency in Kubuntu Oneiric

5. Go to Global Shortcut Settings -> run Command Interface (in KDE component) -> Lock Session. Change shortcut from there.

1. AFAIK you cannot make just the Super key open the Applications menu. The default shortcut for this is Alt + F1
2. The default shortcut for the System monitor is Ctrl + Esc
3. There is no global shortcut for it, but you can set one. (KDE component: KWin, action: Show desktop)
4. There is no global shortcut for it, but you can set one. Note that the file browser on KDE is named Dolphin. See this answer on setting shortcuts for applications.
5. Ctrl + Alt + L locks the screen.

The default shortcut to get the Run dialog is Alt + F2. This can be mapped to Super + R as well. (KDE component: Run command, action: "Run command")

The global shortcuts can be controlled to the Global shortcuts configuration module. Open the Applications menu and search for Global shortcuts.

There are several ways to create mapping keyboard shortcuts.

In system and settings you'll see an option for this (It may be labeled under "Shortcuts and gestures" or something like this -I'm not using an English version so titles may differ a little).

In order to assign shortcuts to task manager or to any widget that may be placed in any panel or desktop you can right click on it (or ALT+D, S) and then select properties option in the resulting menu. After that you will be able to assign a combination of keys that will launch that widget.

Finally if you want to assign a shortcut to a certain program you can always edit the kmenu and then select the desired menu item and assign a shortcut under the advanced tab.

Under any KDE 4 + There is an application called System Settings.

You'll find a section called "Shortcuts and Gestures". You will find every action possible there and will be able to assign any keyboard to any gesture and even create your own ones.

Don't be afraid of it, it's really easy to use and you can set "main shortcuts" and "alternate shortcuts" so you don't even have to remove the original one :)

for (2), I wanted to kick away the default key binding for the 'system activity' so it won't be Control+Escape. Unfortunately, on my Ubuntu 12.04.3 I couldn't edit this shortcut anywhere in the system settings menus, and I searched well there.

Solution: Edit ~/.kde/share/config/kglobalshortcutsrc Search there fore 'ystem' and find the line like this:

Show System Activity=Ctrl+Esc,Ctrl+Esc,Show System Activity

Simply change it to your liking. In my case:

Show System Activity=Ctrl+Alt+Esc,Ctrl+Esc,Show System Activity

That did the trick for me :-)