My pastor believes there is a difference. He is vehemently against it. Basically, he argues that there is a big difference between renting, buying property, goods and services from unbelievers and pagans (we all do it during our daily course of business) versus giving your tithe knowing that it (or a portion of it) is going into the treasury of a cult or heretical sect. He makes a fairly convincing argument. Personally this is something I've never given any deep thought or study to, so I'm curious what others think about it.