I personally don't use candles for Guided Meditation, but I keep hearing from people how adding that one more sensation helps you relax so much better.

Sandra over at craftgossip has this to say about it:
"Aromatherapy, combined with candles, meditation and positive affirmations are nice ways to start the morning or end the day."

I just may raid my wife's candle collection and try that out next time I sit down for some guided meditation.