I am using Ubuntu 11.04 and because of Unity switched to LXDE. Now my system is fast and I like it. Here is a first trick found on the Internet:
cd /usr/share/lxde/openbox
sudo leafpad menu.xml
Now you can add in the Application Menu whatever app you like:
<item label="Opera">
<action name="Execute"><command></command>opera</action>
</item>
This is an example of my application menu:
Do you have any other trick or tips regarding LXDE? For example how to change all the icons like on Gnome with different themes? From where to download LXDE themes? Do you have good resurses for LXDE(sites)? Can you show us your LXDE desktop?