And for reference: 

well shit.
That's incredible :O

Kind of looks ... small?

Guess it is not blowing me away or anything. Still looking forward to it though. Is this the whole thing, or just one part?

It's an island? Weird.

In every GTA the city is an island.

So the city of Los Santos itself is essentially the same size as GTA4's Liberty City. Cool.

I cant wait to explore everything. All dat land. All dat sea.

It's definitely massive, at least 3 times bigger than San Andreas, or 5 times bigger than IV. It's hard to really comprehend the scale of it all looking at the map.

Some screenshots to help put it in perspective: 

Really? Guess I'd never noticed before as my most played GTA's are the Liberty City ones.

Game looks great. Can't wait to get it.

Atleast every 3D Game.