There are all kinds of candles that one can use for prayer and magic. The kind I use is sometimes frowned upon by more traditional sort of magicians. I like to use tea lights, because they are inexpensive and convenient to use, and easy to purchase from almost anywhere. Coloured ones can be gotten from specialty candle shops. Tea light candle holders are also abundant, with so many shapes and designs to choose from it can be confusing.
Tea lights are ugly by themselves, it is true, but not if you do them up nicely. You can be very creative with tea lights, like this "open" container spell. Now, it is worthy for the spirits.
People ask me how then do I anoint tea light candles with occult oils. I anoint them clockwise for increasing, and counter-clockwise for decreasing while focusing my intent. (For tapers they anoint the candle from the foot to the wick for increasing/drawing, and the opposite direction for decreasing/repelling.)
Surprisingly divination signs can also be read from tea-lights, sometimes knobs in the wick form, sooty burns and unconsumed wax occurs. Tea lights are also good for the tops of honey jars, because they generate alot of heat and heat makes for the spell to work faster.
Of course there is no "best" candle type to use. It all depends on the conjurer. For example my friend finds that tea lights are completely useless for her.
She much prefers traditional tapers, because the oils burn more evenly and they are more direct, melted straight onto the container spell and lit. It even "moves" from something tall, it "grows" short. Very symbolic, as if symbolising things happening in the physical world, or the spirits consuming and feeding off your offering.
Votives are rarely used by my person. I dislike the cleaning associated with them after, it is hard to keep the glass sparkling. But what I do like about them is the fact that they can be snuffed out and lit again only while working the spell, at the same time looking innocent as if it were for aromatherapy. They also seem to feel "cleaner" than other candle holders. (I guess it might be a psychological thing because glass is clean and shiny and therefore it must be clean and "pure.")
The most unusual type of candles I use are tall pillars, that take many days to burn. They are just like glass-encased vigil candles, without the glass and can be rubbed with oils outside and dusted with ground herbs. Can even be studded with herbs no problem. I advise people to buy them good quality ones that burn without running.
Oh how I love candles. Just looking at how they burn and the flames dancing makes me all happy inside.