Personally I would go with reg'ing both the com and org and forget the others you mention, in most cases. Often only reg'ing the com is best (if available). At times I feel the org works as well, perhaps even better for some specific categories. They are both good. Rarely would the net biz and info be worthwhile, IMO (unless it is a flagship website).

From my experience, I would suggest to register .com or .net, any dots are not effective to the customer. I mean, it's so difficult to remember or promote (from marketing perspective).