Atlanta is growing, bustling, modern and provides all of the amenities that one would expect to find in a large U.S. city,  but its cost-of-living is less than in other major metropolitan areas, including Boston and Washington, D.C.   Real estate is booming here, and you will find just about any kind of housing you can imagine, from starter homes to established neighborhoods, from condos and town homes to restored lofts, from cottages to Victorians.   It is all here.  Homes prices begin as low as $100,000.