Hi,
I have to HDDs-Samsung SP4002H (40 GB) & Samsung SP0802N (80 GB). HDDLife shows the normal temperature of the 40 GB disk in between 40 & 45 and for the 80 GB disk, it is between 45 & 50. While defragmenting or when doing some hard disk intense tasks, the 80 GB disk's temperature rises to 53. Once I saw HDDLife showing 55. I shutdown immediately. I don't have a problem with any of the disks so far. I have been using the 40 GB one for three years and the 80 GB one for 1 year.