Have you tried System>Preferences>Appearance? Click "Customize" in the "Theme" tab to change icon theme and window borders etc. or click "Install" to add more themes. You can look for new themes at
Originally Posted by undfined
Some of the themes have installation instructions, but normally you just have to unpack them and then choose the right file after clicking "Install".
To change individual icons (select System>Preferences>Main Menu (or right click on the main menu) and then choose the application you want to edit) right-click on the applications icon and choose properties. Click on the icon that you want to change, you will be presented with a "Browse icons" window. If you can't see an icon that suites you click on "Browse..." and navigate to your downloaded icon. It might be a good idea to copy all your icons to the /usr/share/pixmaps/ folder, but you will need root privileges to do this. One option is to
Please be careful with root-privileged-nautilus.
To enable compiz fusion, try the "Visual Effects" tab in System>Preferences>Appearance. If you want more options with compiz, you can try compizconfig-settings-manager from Synaptic or
sudo apt-get install compizconfig-settings-manager