I tried the Ian Knot, found it fiddly to tie. I use a standard knot by force of habit or when I can't stand having unties, or the laces are long, I use a Surgeons Knot.

The Surgeons Knot is just a standard shoelace tie with 2 slight modifications - when you overlap the 2 sides of the lace you tuck the lace under twice. This, like a Timber Hitch, creates much more contact area and thus much more friction.

I have (not from that site) switched the way I tie a standard knot as I was doing grannies instead of reef-knots. This seems to have prevented unwanted unties.