it's not really a matter of definitions, it is a matter of magnitudes. most christian religions, most religions for that matter, allow their worshippers to come and go as they please (though they clearly don't want you to leave). you are not harrassed to the point of fear for your life if you choose not to continue to follow. they are also not specifically concerned with taking money from their flock either (though clearly all religions would like something in this regard). you can worship all day, and take advantage of the services they offer, without donating a single penny. neither of these is true of scientology, not even remotely.
cults operate at the detriment to their followers and to the benefit of only their leaders. this is not true of most religions. certainly all religions have some cult-like aspects (any worship fits the definition of cult), but they simply do not meet the conditions generally thought of as a true cult. it's like shades of gray. some are a bit more extreme, mormon and/or latter day saints, for example (no, they are not the same thing), and others are very extreme to the point of actually being what we would normally refer to as a cult, jehova's witnesses, for example.
generally, it comes down to the level of control over followers' lives that is in place.
taks
True. My church (now I am speaking for myself) does not try to control my life besides what every religion or cult does (by teaching). In fact, I am like a friend to my preacher. Heck, I am his friend.