I'm a firm believer in adding one item at a time for a week and seeing how it affects both your cravings and weight loss. Most people do seem to do better eating both fruit or grains/starches along with a serving of protein.
The first two things I added in the past were berries and apples. We love peanut butter with our apples.... nummy.
Personally, I love smoothies, but when we started having them on a regular basis last time around on South Beach my weight loss did completely stall... After some investigation I decided that it was probably due to the fruit being blended and my body not needing to break it down the same way that I would if it was whole fruit... That was just my personal experience, YMMV.
As far as the grains/starches go... some of the first things I added that I did really well with brown rice, winter squash, and oatmeal...
It really is trial and error... just take your time, listen to your body and you'll be fine.