There are many options. Some will say protection and rain all in one, since its sort of designed to work that way. I prefer the layered approach. With the layers having a function. The only real issue might be if you are wearing a layer do you have room to store it.
I ride with jeans, a textile jacket or a leather jacket (depending on the temperature) and layers under (long underwear for warmth and if needed a heated jacket liner). I have ridden in the upper 30's with just long underwear and leather jacket but that was a few years ago. What I found out, was that you should use the rain gear as a seal against the cold as well as the rain. So, when it gets cold out I can put on the rain gear (top and pants) and that really helps.
So, what I have today. Rain gear (Frog Tog paints and a rain jacket, a step up from the Frog Tog's jacket), textile jacket, and thermal underwear. Boots are Sidi boots that are Gortex lined so my feet sort of stay dry and a pair of outdoor gloves I got from a hiking store. Warm and don't really get too wet in the rain.
You mentioned "protection" and I have looked at the combo jackets and always thought, what gets wet if there is a liner to keep the rain out. Does the jacket dry off? So I have always stayed away from the combo jacket.
As I said, jeans with thermal underwear and the rain pants tend to keep the lower body covered.
Another thought is the new Warm-n-Safe Jacket liner which is suppose to be resistant to water (have to look at their web page to see what it actually says but I'd always wear an outer waterproof/resistant layer.
One more thing, a neck gaiter, keeping the next warm is essential in keeping the body warm. I just one almost all the time when the temperatures are below 70. It really makes a difference.