Having live media that can boot both ways can be a problem when installing Ubuntu onto currently available Windows 8 computers.
In other words the key advantage to creating UEFI-only bootable USB live media is: You know that it definitely booted and installed via UEFI.
Since Valve has already been doing UEFI-only booting USB installers with their Debian-based Steam OS and UNetbootin — the top voted alternative to Ubuntu's Startup Disk Creator — isn't UEFI compatible and therefore misleading, I think we should have a separate topic for creating UEFI-only bootable USB live media.