I would expect it to be the first quarter 2013 before we get our hands on this, late 2013 for the PC if we're lucky.
GTA is too big in it's own right to be a holiday season release and they tend to hype it up for a year as well with lots of press and previews.
Going by the logo it doesn't look like it will be Vice City which is a bummer as it remains my favourite GTA, not necessarily the best but the one that hit all the right 80's notes with me
Los Santos is what the logo reminds me off immediately based on their Midnight Club LA South Central expansion.
Still, I am yet to be disappointed by a GTA game, the older I get the less I become tolerant for corny cliche type of games and I love games that little bit more grounded in reality, GTA, Red Dead, Assassin's creed do this very well. Despite the criticism that GTA IV took itself too seriously I really liked the direction GTA went and I hope that V will equally maintain that direction of becoming a more mature game.
Glad to see it finally becoming official though!