Yep, half a billion. Not that anyone really needed convincing, but computer games are big business. This one eclipsed the record set by Halo 3 last year.
And games are only going to get better.
Interestingly - but I can't find the reference (send me the link if you know it) - I was told last week that the average age of a gamer these days is 37 (this link from 2 years ago pegs it at 33).