That's a cool link, Irene!
Mokelumnkid--
just off the top of my head, here's what I find most essential:
-The Bowline. (and Bowline on a bight)
-Double Fisherman's (for tying prusiks)
-The Half hitch, trucker's hitch, ect
-The figure Eight series
I like the Butterfly knot, some don't. It's not listed on there.
I find those knots are really all I ever need.
A Double Sheet Bend is good for tying two lines of disimilar diameters, and the Klemhiest knot is just f**king cool as sh*t.
anyway, great link Irene!