Sorry for the double comment. :/ It won't allow me to delete either.

From thefreedictionary.com: "To kindle is to cause something gradually to begin burning; it is often used figuratively: to kindle logs; to kindle someone's interest. To ignite is to set something on fire with a sudden burst of flame; it also has figurative senses: to ignite straw; to ignite dangerous hatreds." Kindle and ignite are both acceptable, but I definitely wouldn't use kindle to describe lighting a fire/lighting something on fire. I would only use kindle figuratively to describe a gradually increasing interest.

From thefreedictionary.com: "To kindle is to cause something gradually to begin burning; it is often used figuratively: to kindle logs; to kindle someone's interest. To ignite is to set something on fire with a sudden burst of flame; it also has figurative senses: to ignite straw; to ignite dangerous hatreds." Kindle and ignite are both acceptable, but I definitely wouldn't use kindle to describe lighting a fire/lighting something on fire. I would only use kindle figuratively to describe a gradually increasing interest.

Google kindle, fire = 566,000 hits Google light, fire 2,300,000 hits . While not exactly rigorous, I think we have a winner. :)