OK, so this thread got me going on knots.
I was curious about what a bunch of Internet knot folks thought were the most useful, most basic, most need-to-know knots, so I did a search and found a few threads including one on the
International Guild of Knot Tyers Forum - Index (these guys are hard core). I went through all of the posts and put the knots in excel and counted the number of hits on each. For some, like the bowline, there are several variations, and I put those in just as the "bowline". I figure if you learn how to tie a bowline, then the variations shouldn't be too hard to remember/learn.
The list is about 80 knots. Here are the top 15ish in order from most often mentioned to least often mentioned. What I found interesting is that a bunch of the knots that knot folks seem to value aren't knots that I'd ever learned or heard of in the boy scouts. I've seen the figure 8 knot a hundred times, but never knew it was a knot. It seems to find it's way into hoses and extension cords a lot. I guess it's easy to end up with a figure 8 knot if you mess with coiled lengths of stuff (hose, cord, rope, etc...)
bowline (includes water bowline, double bowline, bowline on a bight, etc...)
figure 8 (there are also several variations of this one including a bend and a loop. )
alpine butterfly (bend and loop)
square (funny, since the square knot seems to be generally frowned upon)
clove hitch (same here, like the square, this knot is the jack of all trades master of none)
constrictor knot (I didn't learn this in the boy scouts, but this is a good knot)
truckers hitch
sheet bend
zeppelin bend
double fishermans bend (prusik)
overhand (includes the double overhand, slip, etc....)
tautline hitch
half hitch
carrick bend
adjustable grip hitch
buntline hitch
timber hitch
I came across this video and thought it was pretty cool. I like the quick method for tying the bowline.