Once, a long time ago, on a POSIX real-time operating system, I was logged in as root with "su -", and had cd'd to /. Some time later, in a distracted minute, thinking I was still running in a user, not root, shell, I executed the command "rm -rf *"... Hilarity ensued! Doh! One thing about sudo, is that this won't happen, unless of course you have executed "sudo su"! :-) So, for my own purposes, I am ambivalent about either approach, although I do configure my Ubuntu systems to allow root logins; however, I do use a strong password for the root account - you need a good Sanskrit dictionary, along with some physics to derive it... I expect that the universe will reach maximum entropy before anyone can guess it!