I don't know, to be honest. I take the position of the middle way and hold the three marks of existence. Nirvana is my goal, and experience and the way are my teachers. My practice is meditation and contemplation. I try my best to recognize things for what they are. I don't have much to be committed to, but to a clear and open mind, the understanding of all people and things, the shedding of my ego and compassion.
I think I have the fundamentals, and I know I have none of the rituals or traditions. There are many teachings in Buddhism, but I feel that the fundamentals can get me a long way. I judge all the other teachings I run into on the fundamentals anyways. And why do I place my "faith" in the fundamentals? Because I think it's a defendable position xD It doesn't say too much nor too little, it speaks for itself. It's only one perspective among many, but try to apply it to the world and you'll see it's a good one.
The "inside" practice, what goes on within your own head and the privacy of your own home is not only useful, but fun! Then there's reincarnation. Some interpretations don't use a "soul", but transfer of "mental energy", which is to say, a soul. I think that belief is hypocritical and don't put much stock in it. I find it a weak attempt to reconcile selflessness with life-after-death.