GTA 5 will launch November 18 on PlayStation 4 and Xbox One. It features a first-person mode, new weapons, additional wildlife, denser traffic, improved foliage / weather systems, enhanced damage models, over 100 new songs added to the radio, and a lot of other improvements.
Rockstar is also giving $1,000,000 in-game money ($500k story mode / $500k GTA Online) to those who pre-order the game. No news on the PC version of GTA 5 yet, but we do know it is currently in development. It may be taking longer because of how much of the game has been remade to include improved graphics and gameplay features.