Quick question about time machine: does it allow the user to set up multiple backups in addition to the general "backup my entire machine" setting? For example, can I set a specific folder to backup to a second external hard drive?
Yes, technically you could make a case that this is user-specific backup, but right, who wants to exempt all but that 1 thing you want to save? It seems to me alongside the "exempt" feature they could easily add "add to backup" and let you cherrypick what you want.
If there is only one thing you want to save, and you are sure what that one thing is, then just duplicate it or use any of the numerous cheap to free applications to back it up.
For the 96% of people who do not back up regularly, and whose "one thing" will be the thing they mistakenly trashed or the file they didn't know became corrupted, Time Machine is a dead simple way to back up all of your drives without having to think about it.