This newsletter has carried several articles over the years about the life expectancy of CD-ROM disks created on home computers. In short, the news is not good for genealogists who wish to record data once and then store it for many years.
Now a new article on WarehousePhoto.com gives details on the different types of blank CD-ROM disks available. It points out that the cheaper disks may not last two years. The article concludes, "You generally get what you pay for."
You can read all the details at http://www.warehousephoto.com/How_Permanent_is_your_CD-R.htm
(The article has an amusing typo error in the first sentence but otherwise seems to be accurate.)