Nautilus Easy Union is a Nautilus extension (comes as a stand-alone application too, but it requires Nautilus anyway) that allows you to create a "union point" which is basically a folder that displays the contents of other (multiple) directories. You can use it for easily accessing all your pictures, music, videos or other files from a single location.
To understand better what Nautilus Easy Union does, here's an example: suppose you keep your videos in multiple folders like: /videos /home/your_username/videos and /sdb3/videos. Using Nautilus Easy Union, you can create a folder that lists the contents of all these 3 folders. This new folder will display all the files in these 3 directories. You can also write to that folder - Nautilus Easy Union has an option which allows you to select the actual "real" folder where the files will be written.
Here's a video I've just recorded demoing how Nautilus Easy Union works:
(Watch it in HD)
In the above video you'll also see how to set up Nautilus Easy Union "union points" and how to remove them.
Install Nautilus Easy Union in UbuntuNautilus Easy Union comes with a PPA now so to install it in Ubuntu, use the following commands:
sudo add-apt-repository ppa:zanko/daemontux-stuff sudo apt-get update sudo apt-get install easy-union-nautilus nautilus -q
For how to use Nautilus Easy Union, see the above video.