This interests me too.
I have just got my toes wet with Linux, with a huge amount of help
from various people.
And at the moment I have dual boot and use Acronis in the other system (MSW)
My take on this issue is that I am glad I have dual boot with a
complete mirror of the whole drive as the problems I am encountering
with setting up Linux is more than I am currently capable of without help.
So a simple backup drive from Ghost or Acronis is a godsend to me.
I think some of the comments about just saving data and then rebuild
the OS are a little bit inconsiderate of total newbies like myself.
Not very encouraging to for people to in fact use Linux OS.
So in conclusion a clean backup saves me bugging kind people more
than once on the same subject.
With respect
Eric Brackenbury