My preferred solution when using FCP7 is to keep all my .FCP files in Dropbox.
Dropbox acts like a normal folder on your hard drive so you can open and save as normal, but it's also continuously backed up to the cloud as well as all your other computers.
This means you can edit on your studio Mac Pro, then go home to your loved ones safe in the knowledge that you have a copy of the edit on your laptop*.
If you client has all the media you can also log in to DropBox online and get the .fcp file anywhere in the world.
Plus .fcp files are only ever a few meg so you are pretty safe with a free DropBox account.
For me it is a great way of working for backup reasons alone.
So how does this all work with FCPX? What about all those stupid events and project folders? What's with the new library files in 10.1? Can you store them in DropBox? Or are there too many associated files hidden inside?
I have no fucking idea.
But I'm going to find out.
*Providing you have all the relevant media on you of course!