UAC is a pain the the ass and is best turned off for anyone who (basics) knows what msconfig is for.
Absolutely, categorically, utterly disagree 100%.
If anyone feels the need, for whatever reason, to run as a privileged user, UAC should be properly enabled. There are far more ways to get software running at boot than msconfig can show. In fact, most legitimate software will use these same methods. Disabling UAC whilst running as a privileged user invites any running process to have complete control of the machine (and entire network, as I've seen some pillocks run day-to-day as Domain Admins etc). Its like running a Unix or Linux system, and only logging on as root.
Since the advent of consumers using an NT kernel, which for most was XP, there is no concept of TSR - the OS enforces a proper, preemtive multitasking system.
Sorry, security is a pet hate of mine, seeing as I seem to spend too much of my working day initially firefighting, then clearing up the aftermath of people who 1) are too stupid to use technology, or 2) think they know more than they do about their computers, in the process severely impacting other users of the ISP

. Especially when 99% of the time its easily avoidable, and for free.