I used to use significators in all my readings, but I found when choosing that sig. I was biased, so I progressed to letting the deck choose one for me. Now however, I do not use one, and usually find that if I need one, the deck throws me one anyway. I also find now, after reading the cards for quite a while, I can recognise who the cards are talking about by which cards it throws at me!
On my first date with my boyfriend, I gave him a reading. The Fool was thrown at me as a significator for him, as was the King of Swords. Then, it threw out the Queen of Wands as me... It's been like that ever since! (Needless to say, that reading told us what was gonna happen between us in the future, but at the time I didn't wanna say anything just in case he thought I was biased...)
"Pistis Sophia: the Goddess Tarot" (forthcoming) http://pistissophiatarot.com
"Tarot 101: Mastering the Art of Reading the Cards", by Kim Huggens, released by Llewellyn Worldwide, 2010.
"Sol Invictus: the God Tarot", Schiffer Books, 2007.