If by "best" you mean the helmet closest to the real helmets, you want a "Mystery Helmet," which is actually a misnomer at this point because we more or less know what it is.
It is the only helmet available to fans with a linneage to real helmets.
That being said, there are a number of other alternatives that may not fit the accuracy bill as well as a Mystery Helmet, but they have other features that make them quite appealing depending on what you are looking for.