I think I read it on Elitist Jerks or whereever, that taking either the LB or the LvB glyph does have to do something with the current state of your gear.
So, it wasnt stated which one to use in which case...here's my armory, I'm currently using FS/Unleashed Lightning/LB glyphs.
http://eu.battle.net/wow/en/characte...nn/Feio/simple