After only 2,300 years, the dripless candle has come to be. I remember reading about how this miracle could be accomplished by simply using a harder wax on the outside of the candle. The heat from the flame melts the softer wax of the interior, while the further-away outside wax still holds its shape. It sounded so simple, but nobody seemed to make candles that way. Feeble attempts gave us candles that dripped less, but weren't truly dripless.
Until, of course, IKEA came along. The last time we were at the Sacramento store, we bought a box of green candles. (Somehow, we seem to be using the color green to accent things in our new house.) We burn a candle during all of our meals every day, so we go through a lot of them and really appreciate dripless ones since they make it easier to keep the candle holder nice and clean.
So remember when buying candles to get ones with harder outside wax. How you determine that before purchase I don't know. Simplify things by going to IKEA. Their stuff works.