How does the church regard magicians like David Blaine?
Nowadays there are two types of magic: one is an entertainment magic and the other is the one condemned by God in the Holy Bible.
David Blaine like many others, Houdini, Sigfred & Roy, Lance Burton, David Copperfield, to name a few, are all illusionists. They are excellent in entertaining people deluding them into believing what they think they see. A magician called Craig Browning wrote "People want to believe in magic and we are the instruments via which that experience can become manifest". The techniques of many of these tricks are now available in books that people can buy and try to practice themselves, even levitation. To keep yourself three days in an ice block or bury yourself alive or make the statue of liberty disappear in front of a huge audience are all very entertaining acts; and those who perform them call themselves illusionists.
This is different from the "magic" referred to and refused by the Holy Bible which is, without exception, the manipulation of the supernatural realm, either by conjuring of demons, consulting with people known as sorcerers or mediums, dabbling with astrology with the intent to predict the future. (Deuteronomy 18:10-11)