The problem Rami describes on his site is with NVidia drivers. Since a virtual machine doesn't emulate NVidia hardware (regardless of the actual hardware on the physical machine), then his solution does not apply. That said, I always run without rhgb. It a) boots faster, and b) shows more info during the boot.

To disable rhgb temporarily (for a single boot):

• Boot the VM.
• When you see the graphical Fedora boot screen with the "Booting Fedora Core in 5 seconds..." countdown, press any key.
• Use the up/down arrow keys to select the kernel you want to boot.
• Press 'e' to edit the selected kernel's boot parameters.
• Use the up/down arrow keys to select the line starting with "kernel /vmlinuz-" (probably the second line).
• Press 'e' to edit the line.
• Use the left/right arrow keys to move the cursor, and the delete key to remove "rhgb" from the line.
• Press enter when finished editing. This will return you to the kernel parameters screen.
• Press 'b' to boot the kernel.

To disable rhgb permanently:

• Boot the system and logon normally.
• Execute "su" to become root.
• Use your favorite editor to edit /boot/grub/grub.conf.
• For each of the installed kernels, remove "rhgb" from the line(s) starting with "kernel".
• If you don't like the graphical boot "splash screen" and you want a normal grub menu when you boot, you can also comment out the lines starting with "splashimage=" and "hiddenmenu". Just insert a '#' at the beginning of these lines.

Good luck!