going to have to say live sand, exspecially if you want coral down the road. CC is fine if your doing a pred tank, but some preds like to sift through the sand. i would go sand either way.
when you go to the LFS, they should have a brand called carib-sea. thats what i use and its very good sand. it should be aroud 25.99 for a 20lbs bag. price could be higher or lower depending on your area. when you clean the sand just stir the surface of it a little bit, dont get all the way down there, thats really hard on the tank.