There are several items that need to be part of your SharePoint backup/restore plan.
SharePoint Application Files
Custom Applications (such as webparts, add-on “features”, etc.)
If you are performing a complete, exhaustive backup of each SharePoint server, then the first two should be fine (some custom apps will need dlls, etc. on the file system), as well as some of the IIS Info (web.config for each SharePoint application, for example).
The remainder of the IIS Info can be captured via a IIS Metabase backup. Remember, changing some items within SharePoint's Central Administration will change the IIS configuration and so this backup needs to be done on a regular basis.
If you are following best practices for backup the databases, then you should have this one covered as well.
I personally have a script that on a scheduled basis performs an stsadm backup of all my site data. I keep a “rolling” week's worth of those backups on my server and it gets backed up using file-system backup software. Also, the backup/restore functionality provided within SharePoint's Central Administration is a wonderful too, however it can't be scheduled. During my latest (notice I didn't say my only) crash, I used these backups to restore my environment.
I suggest picking up a good book that has some more detailed advice concerning the topic of backup/restore. A good book I have purchased and am looking at right now is entitled “Real World SharePoint 2007: Indispensable Experiences From 16 MOSS and WSS MVPs” by wrox press. In Chapter 3, Todd Klindt gives some good insight on backup and recovery.
Also, make sure you give a good read to the Technet article: Choose backup and recovery tools (Office SharePoint Server)
In response to SharePointU post here: http://www.sharepointu.com/forums/p/2994/8014.aspx#8014