
God haven't heard that quote in a while!
I'm starting to think that there isn't a one fit solution for this. The way I see it you have 3 groups of people
1. Never need auto tag.
2. Needs a fast changing and flexible auto tag system. (I guess your latest idea fits here)
3. Needs a few tags easily selected that change rarely. (My idea here I think)
To be honest When I am at work I would firmly sit in group 3. But at home would move more to group 2.
From a group point 3 point of view, when I first get into work in the morning I am barely awake, and have a standard pattern of work to do whilst I wake up (Coffee, Toilet, more coffee, E-mail, BBC news, More coffee, check error logs, breakfast and by that time I am Human again

) I wouldn't like to add the task of setting up the same old tags every morning.
Yet at home, whilst doing a distance learning course (Object Orientated Principles in Java currently but always have at least 2 different courses on) I would be tagging clips for only one subject for an hour or two and then changing my subject matter and therefore my tagging requirement.
I think we need some more input by other users to see if they can move the idea along a little more.