Back up your crap
Looks like someone over at UF, with a hard drive full of priceless music and photos, decided to screw around with Gparted without backing up...
Guys, anything important to you, BACK IT UP. Years worth of files can be gone in less than a second.
Mac users may be familiar with Time Machine - A backup program included with OS X. If you have a Mac, plug in an external hard drive, and it will make copies of all your files hourly. You can then use an interface to go "back in time" with any of your folders. Here's a screenie:

Time Machine for Mac OS X definitely wins in terms of easy, seamless backups. But what about our Windows and Linux friends?
For Linux, there is a similar program called Time Vault with the same idea. Seamlessly back up to an external drive and "go back in time" whenever you need to. Here is TimeVault's home page on the Ubuntu Wiki. The UI may not be as cool as Apple's, but if you're the type who never backs up, or is just too damn lazy too, you should consider trying this out. Here's a screenie:

And finally, our Windows users. Seagate has a solution called Replica that works pretty much the same way, although there is a catch, you have to use their hardware - you can't use just any hard drive. Damn anti-semites.
Of course, this is just the start. Even if you have 200 enterprise-class hard drives RAIDed together for the ultimate backup solution, what happens when your house catches on fire, or you get robbed? Gone. Another thing you should do for those really important files is off-site backups. I would do one or more of the following:
- Put a copy of your system on an external, then store it at a (trusted) friends house.
- Register with JungleDisk (or something) and store your important files on their servers. (That wasn't an affiliate link, I swear)
- Put your treasured files on a flash drive and keep it in your anus (kidding)
And remember, never EVER screw around with partitions or hard drives without first having a working backup.