Currently being released on 17th September, GTA5 will be set in Los Santos, in the state of San Andreas. Rumoured to have the biggest game map of all time, supposedly bigger then the worlds of Red Dead Redemption, GTA San Andreas and GTA 4 combined! In a first for the series, you can also switch between the campaigns three main protagonists during gameplay, with each character having his own special skills, such as rappelling down buildings, a sure-shot with a sniper rifle, or being able to fly a helicopter with ease.
As for DLC, Rockstar have stated that they have planned alot of interesting stuff to be released, but at the moment there isnt any information.