Hmm lets see an addiction is something someone has tried and it has become out of hand and then becomes the ruling force in a persons life..(without looking it up in the dictionary that is close)
I would say that yes an addiction is always bad. An addiction would cause you to do things you would not ordinarily do to fill this need that the addiction requires. Be it drinking, drugs, food, chocolate, sex, (cough) computers..
Love... I am not sure there is an exact answer to what love is as I think it is unique as the person who is in love.. I have never had the same love with any one person. Love is something that grows with time spent together, closeness,whether like minds or opposites, love is a combination of desire, compassion, understanding, communication, passion, companionship, respect and trust.
love an addiction... no I don't think true love is an addiction. But some kinds of love can become an addiction. Such as a Battered wife, a stalker, obsession, someone who "needs" someone else to feel complete.
I love my husband. I don't "need" him to be complete.. I want to spend my life with him. Our lives are still unique but we compliment each others intrinsic needs.
We share our live's to make them more complete. We desire to be together. But unlike an addiction we could go on without each other if need be.. Don't want to but could. Especially if the line of trust was crossed. Love is a choice. Addiction is not.