I have Ubuntu running as a vm in VirtualBox at the moment, but in the future, if I want to dual-boot it with Windows or another OS installed on my hard-drive, what partitioning method should I use to make room for it?

1)Manually partition my hard drive via disk management in Windows (or the equivalent in another OS), making appropriate room for the main partition upon which Ubuntu will be installed and swap space;

2)Partition via the Ubuntu installer options;

3)Use gparted or another free tool like it.

I am uncertain as to why I would want to use one over the other.

Lastly, am I correct to think that it would be the acme of foolishness to try to partition drives within a virtual machine (since that partitioning would be inherently limited to the limitations set upon it by the virtualization software, e.g., VirtualBox)?

Thanks!

P.S. Oh, and I am also planning on not modifying the MBR of Windows if I ever do dual-boot with Ubuntu, using instead a piece of free software (like easyBCD or something) to avoid the headaches of Grub being overwritten by a Windows update.