This question is somewhat open ended, so I'll describe the specific issue, what I want to accomplish in general, and what I tried to do. It'd be a little long, but hopefully not too daunting.
For quite a while my approach to multi-OS boots has been to install each OS to a separate disk. When I want to boot a specific OS I change the boot drive in the BIOS. I find this convenient for several reasons, but mostly because I don't get boot manager conflicts. If I remove a disk or change the OS on it, this doesn't affect the booting of other OS's.
Note that when I say multi-OS, this meant until now multiple versions of Windows. I've occasionally tried some linux distros on VirtualBox, but now I want to do a full install, and see if I can use it as a main OS. (What prompted this was the recent release of Wine 1.2 and the fact that my new job doesn't involve any Direct3D or DDI work. I've always been partial to the open source movement, but I'm also fine with Windows and never before felt I could make the move without losing key abilities). My plan was (still is, if I can get it to work) to use Linux for everyday e-mail, web browsing and such, play Windows games over Wine, and install Windows 7 in VirtualBox for Windows development.
I currently have two disks, one with my main Vista x64 installation, and the other with a Vista x86 installation which I used for my previous job and I no longer need. This is the disk I want to use for the Linux installation. It has a lot of partitions but quite a bit of free space (since I copied a 80GB disk and 250GB disk into a 500GB disk and haven't taken advantage of the extra space).
My first choice of distro was Linux Mint, since it's known to be friendly to new users, and I like the software installer on it. I installed Linux Mint in the past in VirtualBox, and the latest version also installed fine, and I found installation instructions explaining how to provide my own partitions, but the installation failed during the "configuring hardware" stage. If you're interested, more details are available in this thread
on the Linux Mint forums. I didn't get any reply to that thread.
I thought then that I'd try openSUSE 11.3. The live CD looked usable enough, but when I tried to install I couldn't tell how to make sure that I don't get a boot manager which will try to give me access to the Windows versions on the disks. I don't want this, and what I'm really afraid of is that an install will screw the booting of Vista x64 on the other disk (which, granted, I can disconnect for the install, but I'd rather not). At that point I decided to post a question here.
So hopefully you understand what I want to achieve. I don't much care which Linux distro I install, but I'd rather have one which gives me as much usability out of the box (or easily installable) as possible.