I do it for my job (not Ubuntu but HPUX, Solaris, RedHat)
sudo is very powerful and is great for dishing out certain commands to application developers/dba's, to stop them mucking up the whole system. But when you are looking after 800+ boxes, it easier just to be logged on as root. Auditors/Managers etc dont like it, and the reasons are great on paper, but it becomes a pain. As Delta Farce said "sudo bash" will give full root access, same as "sudo ksh" or "sudo su -" assuming sudo is set up to allow such things. Also there are several other back doors that some auditors do not know about, for example "sudo vi file" gets you in to a vi session as root, you can then type ":sh" to get to root shell.

