The drawing in this blog entry shows different cosmological theories, and their prediction for the development of the universe. the Big Crunch or the critical universe seem to be the more logical.Both show a reducing expansion speed since
Big Bang and don't require weird unproven concepts of dark energy which seem to be like the ptolemeic epicycles, even for supporters of the accelerating universe(http://supernova.lbl.gov/PDFs/PhysicsTodayArticle.pdf see
Saul Perlmutter last page)
link to the graph where also the different theories are presented. http://scienceblogs.com/startswithabang/2009/07/15/the-last-100-years-1998-and-th/