I have been doing sitting meditation on and off for about 20 years. Currently im averaging about 30 minutes a day, just about every day. Im no longer sure that im even a buddhist really. I just do my practice and try to pay attention and it makes my life better and me less a pita to the universe at large. If you engaged me in this kind of conversation, you might be unsatisfied with my response, which would be on the order of, "i just do some practice most days and try to live my life on lifes terms and not worry too much about metaphysics or the larger picture".
I dont feel any need to articulate what i beleive or dont beleive and usually when people start these kinds of conversations, i just shut up, and smile and nod alot until i can get away from them. Unless of course they are asking advice about meditation or buddhism, in which case i direct them to some of the local and internet resources, and then i shut up about it.
IMO its better to just do ones practice, it affects ones entire environment and the people in it.
We must respect the other fellow's religion, but only in the sense and to
the extent that we respect his theory that his wife is beautiful and his
-- H.L. Mencken, "Minority Report"