+1 for Ian's Secure Shoelace Knot, though I learned to tie it as the Turquoise Turtle via Brion Toss's The Complete Rigger's Apprentice: Tools and Techniques for Modern and Traditional Rigging
Ian provides a how to as well: Ian's Shoelace Site - Turquoise Turtle Shoelace Knot
I've never had an issue with 550 (or 650) laces coming undone while using this knot. Try it, you'll never double knot again. ;)
Works a treat in Dyneema micro cord (like Samson's Lash It) too…