One per company and most (well, it's ok to have the Sony and Nintendo Portables in their own subareas). The site is just too slow any more to have forum areas for past gen consoles. Those will get hardly any attention 6+ months into next gen.
On a related note, I've always found it a bit silly to have console specific areas AND a general gaming forum. Even moreso now that forum posting traffic is so much slower than in the past. I get that the area works for more general industry news, console war/debate threads, general gaming polls etc. But other than the GGT thread, hardly anything in there gets many posts anymore.
It doesn't really work for multiplatform games--at least not the MP ones. Those need there own threads in each console area so people can arrange MP meet ups etc. as that's what most of the active multiplatform game threads consist of anyway. I guess multiplatform single player game threads could go in General Gaming--but few single player games generate much discussion anymore it seems. And I doubt the mods want to hassle with moving/closing multiplatform threads that get posted in the console-specific areas instead of General gaming.