I just have to say how much I love the way iMovie '09 handles video files.

When you import video, you can save it to any drive connected to your Mac. It will go to a folder named "iMovie Events" on the selected partition.

Whenever that partition gets full and you want to move to a larger drive, you can just move the files to another partition and relaunch iMovie. it will find the files in their new location, no questions asked! And your iMovie projects will continue to work without asking where the source files are.

I wish every piece of software made things just as easy as that ;)