Atlantis is a great program, no question there. For straight text entry I still use a copy of Word 5.5 for DOS under DOS 6.2.2 in a VM machine. Other than that use the Word or Open Office application. Both will suit the need.
Adding pictures and captions to your work is more a function of layout and design. There are many programs that do a superior job to the word processors in layout and design. Write first, worry about design later.