Personally and professionally, I advocate making the decision re: whether to wear a helmet based on the best, most scientific evidence available, not isolated anecdotes. Of course, there are no controlled, causative studies. No institutional ethics review board will approve a study that launches live people into injury without helmets as a control group. Having said that, the retrospective studies available shed some light on the topic, as well as some of the testing being done. I think the evidence overwhelmingly supports wearing a helmet. In some ways this reminds me of the arguments about wearing a helmet in combat operatons. We used to have all sorts of specious reasons for not wearing a helmet. Nowadays, we simply no better.
As for what configuration of helmet, I haven't looked real thoroughly but there seems to be a little less evidence. What evidence there is (again, retrospective review studies and testing on models) leads me to prefer full face helmets. Ultimately, any well-made helmet is better than no helmet. If you simply refuse to wear a full face, don't buy one. Buy the open face that you're willing to wear. I still consider buying an open face at least for the summertime. I don't know that modular helmets are the equal of full face for protection, but I don't know that they aren't. The only test comparison that I've read leads me to think that they are pretty comparable. And they sure are convenient. Maybe that will be my next helmet. How do they compare in weight, anyone know?
As to what helmet I like. My wife and I both have Shoei RF1000s. We bought them because we both wanted full face protection, and these just fit the best for each of us. I almost bought a Nolan, but the Shoei just fit a little better. Same for the Arai.