While I replaced margarine with butter many years ago, there are still times that I choose not to use butter. My friend Sarah, who keeps kosher, introduced me to Earth Balance, a natural alternative to butter or margarine. It is a non-hydrogenated expreller-pressed oil blend. However, it does contain soy, so if you are allergic to soy, avoid it. (See my review of The Hidden Dangers of Soy by Dianne Gregg in Reviews this month.)
I sometimes use it for baking and sometimes for spreads because it is softer than butter. If you avoid butter because you are allergic to dairy but not soy, this may be the answer, And if you want to avoid butter for other reasons, try Earth Balance, better than margarine.