If I had to pick a favorite, the Lark's Head, or Clove Hitch. Turn one of the bights the same way as the other, you have a clove hitch. You can bend either of them in the middle of a line. One handed, make a Turk's Head out of the Clove Hitch, or a Monkey's Fist out of the Lark's Head. Either can slip over both wrists, or ankles (Or 1 of each) I tend to figure 8 up the arms from a Clove Hitch. The Figure 8 knot can't be tied in the middle of a line, but you can pull it tight as a stopper knot on one end. (Like a shoelace, with or without the aglet) The Clove Hitch can be bent in a rubberband, and collapsed into 3 coils. (Or a zip tie with a pipe T on the end. I usually bend it back, and stick a stick through the straight across handle, and the bent end of the zip tye. Flops right out of a back pocket, can be pulled over the the wrists, ankles, or a head if it's long enough.)
[Citation]Names vary from Sailers to Boyscouts to Kinksters. I use the Marlinspike Seaman's terminology.
