fishNphysician's knot is nice and clean and without a doubt a 100%'er.

I have a somewhat simpler knot that incorporates some characteristics of more than one of the aforementioned knots, and is also nice and clean and 100%'er (I tested it in a knot tying contest where each contestant was allowed two knots.....both of mine tested at 100%+).

Run the line end through the eye twice, then wrap the line three times around the main line and run the end back through BOTH loops which were formed at the eye. Wet and tighten knot by pulling both tag end and main line. Done.

Clinch knot and improved clinch knot are lousy knots.....test them if you don't believe me....both will bind on the single loop through the eye and cut it....They were my Dad's favorite knots, but I wouldn't waste my time tying either.