I've been using the backup software that came with my external USB Hard Drive to backup my work, outlook, etc but I've noticed some limitations.  I am currently using Dantz Retrospect Express Version 6.5 and it does a good job as far as it goes.

Good:

• Easy to use
• Reliable - it has been running well for several months
• Conserves disk space by using incremental backup solution to only grab updated files.
  

Bad:

• Can't handle open files (The notorius *.pst problem, where Outlook has it's .pst files locked when it's running.)
• No remote support (ftp, webdav, etc)
• Closed format - one of the good points is also a weakness.  Consider needing to get information of a backup device but not having the software to get it.  What happens when I don't use Retrospect any more but I need to grab something off one of these backups?  The closed nature of the system means I always have to use this software. 
  
• To upgrade to 7.5 professional the cost is $45.00, not bad but this license only covers one machine. 
  

The problem is I don't want to be on the upgrade treadmill, constantly tied to one vendor.  So the search for backup solutions begins...