Heh, welcome world. Newbies always get a ton of replies, so I'll keep mine short and focus on one thing you said. You mentioned the way that Witnesses cross racial boundaries. Yes, this is commendable, but it doesn't indicate that Witnesses have to be the right religion. How many churches do you know that are actually segregated in this day and age?
And, for that matter, did you know that Witnesses were segregated too when it was the common practice in the U.S. and other places? Imagine how "progressive" it would seem today if the Witnesses back then had simply held to the principles in the Bible. From the early days of Christianity, Jews associated with Gentiles; they were all "brothers in Christ". So why didn't Witnesses challenge segregation like they challenged so many laws that infringed on their practices?
Personally my experience has been that congregations today are well-integrated, and people of all colors feel close to each other, but what causes this? Is it the holy spirit? It's actually easy to explain using in-group psychology. You see, Witnesses are more ostracized (or perhaps we should say more self-ostracized) from the community than are, say, people of color. So when a Witness meets a Witness, it's a bit like feeling an immediate kinship when you meet a fellow member of some other minority that you're a part of -- a fellow vegetarian, or a fellow Linux user.
Humans can only divide their groups into so many sub-groups; the desire to belong to something larger can thus cause them to cast aside divisions that apply in the world at large in order to feel a sense of belonging and solidarity with some group of people. It's no different from any club, whether it's a chess club, an atheist convention, or an association of parents whose children suffer from a certain disease; they all bond over their common interest or difficulty and ignore other differences, in the name of feeling a sense of togetherness and mutual encouragement.