However, in Beginning Sharepoint Administration by Gran Husman, he
says
it's not enough: You should also take a backup of IIS configuration
including the metabase.
Its not just the author of book clamming the you need to backup IIS configuration but MSDN also recommends it as explained below,
Be sure to document any customizations that have been made to the
front-end Web servers so that you can configure the new servers the
same way. Such customizations may include the following:
The %COMMONPROGRAMFILES%\Microsoft Shared\Web server extensions\12
directory.
Any customizations that are made to the Web.config file.
Default quota templates.
Blocked file types.
Administrator-deployed form templates.
Database names and locations.
Web application names and databases. Be sure to document the content
database names that are associated with each Web application.
Activated features.
Source : MSDN Moving to another farm and There shouldn't be any harm in backing up IIS Config settings anyway.
Our intention is to have a real backup that would allow us to recover
our complete configuration, users and customization even on new
hardware.
If you have customized your SharePoint farm with custom solutions deployed to it then you will not only have to backup your full farm but also have to keep a copy of 12 hive folder.
As a farm backup will not backup followings: (Source)
- SharePoint Root - Should be c:\program files\common files\microsoft
shared\web server extensions\12\
- InetPub Folder - Should be c:\inetpub\
In our SharePoint farm, our sharepoint is Synchronized to Active Directory, so you might have to backup your Active Directory too.
When it comes to migration of farm, hardware shouldn't matter to restore your SharePoint farm as long as its configured correctly and hardware is full filling SharePoint requirements criteria.
I "personally" recommend having SharePoint server virtualized so that you can easily clone your farm and restore it in few steps.