Back Up!
Everyone talks about how they back up, but do they really do it? Are you backing up weekly? Monthly? I know that I am guilty of not backing up on a regular basis. But at home I have started using a service called Mozy (https://mozy.com/). I am backing up all of my documents for free, up to 2 GB to an online service. I have installed the program and have scheduled it to run at night. This is a free automated way to back up.
I also am currently backing up to CD. I also have an external hard drive that I copy files to. I mainly use the external hard drive to transfer files between my 4 different computers. You can currently find a 500 GB external hard for under $150.
I have just spoken to a Realtor that has lost her whole computer due to a hard drive failure. They now have to recreate their whole database, not to mention losing all of their templates, photos, stored documents, etc. This is not something that you want to do!
Here is an article from CNN Money talking about backing up that is worth reading: http://money.cnn.com/2007/11/05/smbusiness/computer_backup.fsb/