I agree that atheists need to mingle, be together and discuss ideas, become more educated and get support, but the danger of a "secular hub" is that to the christian you have simply become "another religion." This falls right into their "proof" of things. Christians believe that everybody has to serve somebody, and that everybody worships something. This gets so ignorant with them that you are "worshiping" your wife or your stamp collection rather than god.
Believing in the above manner is like christians saying, "see, they are no different than us." It's like saying it is normal to believe in an invisible man in the sky, and that atheist wants to believe something too, and we all know he wants to believe in the invisible man in the sky.
To the christian you are filling a big VOID in your life when you do this. That's what they think they are doing. Christians just don't get it!
And yet the idea pursuing or not pursuing something which might be useful based on "what the Christians might think" is repugnant. Another question I have about things like this (Bearing in mind that I also agree with the need to mingle, be together and discuss ideas, etc.) is "Will this tend toward a homogenization of non believers?" and "if these hubs do take off, will they contribute to our ghettoization?" Being as how we are already a rather iconoclastic group by nature, I doubt either of those things will take place, but they are still worthy of consideration.
Perhaps it's idealistic of me, but I would almost rather we utilize public spaces for our getting together. I remember when I was a Christian, I was a member of a "Glastonbury Fellowship" and we would just meet at restaurants and the like. Right out there where everyone could see us.
I think a "secular hub" can only be a good thing. Don't let religious people get away with linking a sense of community and public spirit to religious belief.