Since I have a lot of various drives spinning 24 hours a day, I'm looking for software that can run in the background and try to predict a HD failure. Most programs I've looked at rely completely on reading SMART data. Personally, I think it might be better to add a scheduled surface scan. Any thoughts? Any recommendations for programs?

Here is what I've found so far:

Active Smart
HDDlife
Hard Disk Sentinel
Advanced Smartcheck
HDD Temperature Enterprise
Hard Drive Inspector
Disk Watchman
Stellar Smart
Drive Health
DriveSitter
DiskCheckup
SIGuardian
Intelli-SMART
DriveSmart