Let me toss this nugget out there ...
Folks say all the time, if you want to know if God exists in the world, just look around you. This works for some people; unfortunately, I don't have that kind of orientation. A tree is beautiful, but it doesn't help me see God.
When I have doubts, what works for me is digging into the language of the Old Testament. I like to sit down with a concordance and just start translating names in geneologies -- it's amazing what you find just by doing that. I also have several wonderful Artscroll commentaries on the Torah, and it's fun for me to read through the collected rabbinic wisdom, verse by verse. And it gets pretty obscure -- why is there an "Aleph Tov" in the first sentence of Genesis? Why is the first letter of the Torah a "Bet" ? Why did Leah have "cows eyes" and what's up with those shrunken heads that her dad had? The rebbis will give you a dozen different answers for this stuff, and I love reading it. And this all comes from the Talmud. I just happen to rely on the 'Readers Digest' version of it in these collected commentaries.
I see the rationalism, the beauty of the language and tradition, and it makes sense for me.
Now, Jesus is Christ, and Judaism missed the boat on that one, big time. So, I'm a Christian and part of the Church that has been since the beginning. And I'll confess, when I hear the liturgy, when I see the icons, when I hear the music, I don't always feel God. This is a shortcoming of mine. For some reason, my path to faith starts with the power of the Hebrew language and the stories of the Old Testament. And I can sleep at night, knowing that for the first Christians, this must have been part of their path, too.
So if folks want to rag on me for the way I affirm my faith, unusual though it may be, let them do it. But that's why I get a little (or maybe a lot) defensive about chunking everything that preceded Christianity.