I created a scale by which to judge these knots. I want to give my valuation of them and ask for your input. Consider it a poll of sorts.
THE SCALE OF KNOTS
5 (highest rating): Absolutely Essential. If you know no other knots, you need to know these. You will use them all the time in Scouting and camping and maybe even around the house.
4: Very Handy. You will use these frequently. Important to know.
3: Occasionally Useful. Yeah, probably worth learning.
2: Rarely Employed or Better Alternatives Available.
1: Basically Ornamental. Little practical use.
And here are my ratings.
Square Knot: 4. I mostly use this knot to tie up the plastic bags from the grocery store so the contents won't spill out all over my car on the way home, so I use this one a lot. On the rare occasions when I have to tie a bandage, it's also useful.
Sheet Bend: 4. The best way to join together two ropes. BSA dropped it from the required knots for a while, which bewildered me. It's back now, because there really isn't another knot that will do what the Sheet Bend can do, and we find uses for it on a lot of campouts.
Two Half Hitches: 3. Really the only use for this is to secure a line to a grommet on a fly or a volleyball net or post. An Overhand Knot would work, if not quite as well.
Taut Line Hitch: 5! This is the one indispensable knot to know for back country camping. You will use it all the time. It's what prevents your flies and tents from sagging and keeps tension on all manner of jury-rigged constructions.
Clove Hitch: 2. The Clove Hitch has only two uses, really. One is to tie a horse to a post -- which is great if you're a horseman, but most of us aren't. The other is in making various lashings, where you could often substitute a Timber Hitch. Plus, Clove Hitches tend to fall apart, even when they're tied correctly.
Timber Hitch: 3. Very secure knot with a quick release, good for use in lashings and moving large, bulky things like logs.
Bowline: 1. Seriously, why do we keep teaching this knot? Yeah, it's nice to be able to tie a loop knot that will not slip, but very few of us do any mountaineering or rappelling, and when we do, we usually use pre-made harnesses. We expend far too much effort to teach this difficult knot to boys when we could be teaching them something else they'd actually use.
Let me know your valuation of these basic knots. Which other knots do you think we should teach Scouts? The Miller's Knot? Surgeon's Knot? The Better Bow?