There is a new version of the IS which is the highest priced, it has a special tripod mode for the IS, which smooths out pans. The old version does not have this.
For handholding even with a shoulder rig, IS is a must especially for the longer lenses. The extra for the tripod IS mode, while it is nice and useful it is not as important as the normal IS.
DSLRs bodies are cheap, making them work for video is not. Plan to spend 2-5K on lenses and accessories.