Thanks again for the replies!!!
You have me thinking, as I said my original plans were for radiant heat throughout and I could go with baseboards instead of infloor (which at this point would be "under floor") for the carpeted and hardwood areas.
I guess what really swayed me away from all radiant was A/C, here is a link to my website with pictures of the home under construction http://www.rtol.net/scornell/newhome.htm
I have plenty of room in the attic for an air handler, any suggestions on the proper way to cool this home if I do go all radiant?