Zoron :
Yes, but if you remove say the Linux drive... that makes it kind of hard to boot in Linux wouldn't you say?
My apologies if I explained it badly. It all makes sense in my head, lol.
Lets see if I can explain it better this time...
You can install any OS in any order without having to worry about if the boot loader will conflict or not if you do this.
Let's take my computer for example. I have three HDDs and wanted three operating systems. I wanted Ubuntu, XP and Windows 7. It doesn't matter the order you do this in as long as you do it correctly.
-Say you were going to install XP first. Unplug ANY other drives, even if they're just for storage. Install XP.
Now that XP is up and running, you can plug back in those other drives if you need something off of them or what not. Same goes for the next installs.
-Ok, XP works. Now you want to install Ubuntu. Unplug ALL drives again including the XP drive leaving only your choice of drive to install Ubuntu on. Install...done.
-Now Windows 7 needs to be on the computer as well. I'm sure you catching on here...Unplug every drive except your remaining choice for 7 to be installed on.
You should have successfully installed three different operating systems with ease and now you shouldn't have any boot conflicts between the OS's. If you so chose to boot into a different OS, you simply go into the BIOS and select that drive to boot. It's even easier with my Gigabyte mobo, like I said before, with the F11 option going straight to a boot selection instead of going into the BIOS. You can also remove those drives if you so chose without worry of errors.
What I meant before with removing an Ubuntu drive was, I had an old computer that I XP one drive and a spare. So I decided to install Ubuntu on that spare. When I did that, it put GRUB loader as the boot manager. Not a big deal...until you decide to maybe get a new drive or it goes bad. I wasn't able to boot into XP after taking out the Ubuntu drive because of the boot manager. I'm pretty sure the only fix was to reinstall XP to replace GRUB loader.