It's possible but only a good idea if you really know what you're doing. IMHO, it's not really a good idea to do this even with just Linux. With FreeBSD, it makes even less sense. With ReactOS, it makes no sense at all (it doesn't have /home; it's based on how Windows NT/2000/XP/Vista does things).

Just mount /home on its own partition. Then you can use the same /home in each (Linux) OS. Beware though, that unless you use the same versions of software on each OS which is sharing this /home, then your settings can get buggered up when the hidden files are overwritten.

It's an addiction. I can't help it.

I run eight operating systems on my machine:

MS Windows XP Pro
Ubuntu 6.06LTS Dapper Drake (primary OS)
Debian 4.0 Etch
Fedora Core 6
OpenSuSE 10.1
Slackware 11.0 (most used OS)
Mepis 6.5
Mandriva 2007

I use Debian's GRUB to access all of them. I boot to all of them each week, usually... except Windows. Months may go by before I boot into that OS. I only have it on my machine to play games.

I started penguin farming as a way to learn Linux on the fast track. I wanted to learn about different package management methods, different desktop managers, etc. If I was asked to pick a favorite, I'd probably have to say that Debian (and the forks... Ubuntu, Mepis) and Slackware are pretty much tied for first place in my book. Fedora and SuSE have their positives and negatives. Mandriva is a nice distro also.

There are so many others I haven't tried yet. My hard drive is only so big. I'll have my secondary system up and running sometime later this year. Oh boy!

I LOVE GNU/LINUX!

I use mostly RedHat-related distros.

Laptop has Fedora on it.

Desktop has dual-boot CentOS5 and 64Studio, spends most of its time using CentOS, and I sometimes boot into 64Studio to do a little recording. I used to use Fedora+PlanetCCRMA for recording, but 64Studio seems to fit a little better for what I do.

I've tried out just about every linux distro around in the last five years at one point or another, either in VMWare Workstation or actually installed. I've also used FreeBSD, PCBSD, OpenBSD, and NetBSD a bit, in addition to ReactOS, Syllable, MenuetOS, Haiku, Plan9, FreeDOS, Minix, QNX, and Solaris; mostly in VMWare.

I keep my sig fairly current with what I am using on my main desktop PC.
I don't share a /home partition. I have so far found it easier to have "data" partitions to hold anything worth saving.
Currently I have a 300GB drive with over 20 partitions. After multibooting for a few years I know what I need and just use cfsisk when the drive is new.
Pay attention to how many (and what size) primary partitions you will need.
Also be aware that it is possible to use QEMU (and others) to run an OS from Linux if your system has enough resources.
Good Luck

Debian 4
Fedora Core 6
Suse 10.2
Gentoo 2007
Ubuntu 6.10
Mandriva 2007
Win XP 64

Looking into adding Slackware right now; and if only my graphics card were supported, I would have moved Solaris and FreeBSD from my second pc to the main one a long time ago already.

I may be removing Win XP, Mandriva and Suse, however; I just don't use them anymore.

Don't laugh everyone but I actually have XP with/and Slackware on four different partitions right now.. I've got Slackware on hda5 "All the Family uses it", hda6 has a custom kernel and downloaded current packages, hda7 is a Slackware-Current Build by alien bob, and hda8 is a Slackware-Current that I'm working on. I'll get Gentoo back on there in a few days for some reason I can't seem to get Gentoo & Gnome to like each other I don't have any problems with KDE, Fluxbox,or Enlightenment.

I thought the liveCD was Gome based???

Better off not sharing a /home partition, then, between the distros. I might just name it /data or something, and let each OS manage its own prefferences.

Do KDE & GNOME have a way to make partitions show up as an icon on the desktop though? At least specific ones? And how would permissions work then? Would having the same logins/passwords, with the pseudo-home directories being set up for those accounts work? Or will I have to go around messing with permissios and stuff?

For the most part, I'll just be working under Kubuntu, but it'd be nice to learn about other operating systems. Especially FreeBSD, reactOS, something source-based, and something RPM-based.

Oh, and of course I'm not sharing the /home directory with FreeBSD and ReactOS; I don't think they could ever work with it properly.

I only boot one system. For the simple reason that I don't have a CD drive (yet) so I can't boot to install anything.

If I could though, I would keep my Debian system, and have Solaris as my dual boot system.

I have the DVDs right here...

My main computer is set up for serious use. So I have two OSs installed. Windows 2000 Professional, and Ubanto Linux 6.06. I use Ubanto Linux the most; I only use Windows 2000 once a month or less for occasional small things.

But these days, with each new release, I feel that UBANTO LINUX is getting very bloated. So eventually I may be switching my main computer to Debian Etch. Certainly, rather than updating my UBANTO LINUX 6.06 to 6.10 or 7.04, I will be installing DEBIAN ETCH.

Just one, Slackware.

I only have one OS on my main computer, and it is Fedora Core 6.
I only have one OS on my sub comuter, and it is CentOS 4.4.

I boot
Windows XP
Ubuntu Fiesty 7.04
Fedora Core 6

one os per pc