Instead of simply deleting and emptying out the trash, are there any files that are sensitive enough that you shred them with a file shredding program?

Me, not really.

If I were to sell my computer, I would make sure to wipe it clean. But otherwise, nothing too sensitive.

BTW, for a free file shredding program, check this out:
http://www.fileshredder.org/

When I sold my laptop I used a program called Active@ KillDisk

http://www.killdisk.com/

It runs at the start-up and replaces all information on the hard drive with zeros and ones in a random order and you can have it make several passes so as to further remove anything that was on the hard drive. I then included a set of restore disks that could be used to do a fresh install of a Windows OS using their own information. I recommend it to anyone selling their computer.

One of my friends bought a computer from some someone using Craigslist. When he got it, the first time he started it up, Windows Vista wanted a Password for the user he bought the computer from. He called the guy, got the password, and got into windows. The person he bought it from didn't do anything except uninstall things he had installed and "delete" his personal files. The reason I put "delete" in quotes is because using a program the allows you to look at files that have been deleted, my friend and I were able to see anything and everything that the previous owner had on the hard drive, even personal information...like really personal...(email account passwords, social security number, credit card information, even bank account numbers and passwords). We quickly ran this Active@ KillDisk program and removed all that stuff from the hard drive. My friend installed a fresh version of Windows Vista and we then ran the program that looks at everything that's ever been on the hard drive and everything that was there before was gone.

So if you're ever selling a computer, run this program for sure before selling it. But have a way to reinstall an operating system otherwise you might have one pissed off buyer!! Recommend a Linux distro if you don't want to pay for a Windows OS. Ubuntu and Kubuntu are similar to windows, and they are 100% Free.

Well good thing you guys aren't evil and used his info for anything.   

We removed it so that if anything like that ever happened we wouldn't get caught up in it simply by having that information even though we didn't use it. But think about it, if the wrong person had bought it and discovered the information....a sad day when the guy finds out his banks accounts have been depleted...