I don't know, I just wish they would announce a date. That trailer came out in about October last year and there's been nothing since. So it's looking like 2013 or maybe, if we're very lucky, Christmas 2012 at the very earliest for GTA V. All we really know is it is set in Los Santos, the fictional Los Angeles in the GTA Universe.
I loved GTA IV. I used to have dreams about it. I took a good 6 months to complete the story line when it first came out in 2008, exploring all the side missions and various intricacies. I replayed it through last year and completed The Liberty City Mile trophy achievement - completing the story in 24 hours gameplay.
When GTA V does come out, you'll see very little of me on here for the first few days, that's for sure.