Multi boot and partition recommendation needed

[vbportal]

Hi,
I would appreciate your views/recommendations on the following
setup (I unfortunatelly have no experience in this area
and reading the respective forums has not entirely
clarified things for me):

I have 3 HDs:
80GB 7200rpm fixed in PC case,80GB 7200rpm removable
and a 20GB 5400rpm removable and would like to have:
(a)a multiboot boot system (XP Home,XP Pro,Win2000,Linux,BSD
and perhaps Win95* and Win3.1* (*maybe not mandatory
as I have an older PC on which I can load this - if that creates
problems)
Note: I wrote "multi boot" but I was also thinking of
maybe not having all HDs active in each setup since
some HDs were removable/could be switched off.
The important thing would be the possibility of
accessing data produced by one OS environment
and using it in a nother.
(b)backup of complete OS,Applications etc


Could you please give me a recommendation on partitioning
(as well as reason/benefits) and any pointers on achieving
the setup.

Thanks,
Vjeko