not fresh, but I've suggested these in the past when this question comes up:
We should add only a very few new forums at a time if we are going to make wholesale changes to the list. Otherwise, it gets to be too much to read/sort through. I imagine it would be hell for the mods, too.
I don't see the point of breaking down the Platforms section into individual consoles or adding a bunch of new genre categories - the forum areas for all these get sufficient traffic now but not an overwhelming amount.
I also don't like the "HS parking lot" idea as a place to kick arguments. It is a bit derisive, and having one's discussion getting "moved" there would probably result in some hurt feelings or possibly people leaving the site. Unless you are engaging in out-right name calling/insulting or offering some other kind of argument without substance, I don't see why threads that engage in deep or heated conversation couldn't be a part of any of the forums. There is a report button and threads can be locked.
Based on what the other posts have suggested, here's what I think makes sense. New forums are marked with ***:
***General Gaming (anything that doesn't fit elsewhere)
Game Reviews (I'd move this up the list as it deserves more attention)
***Games as Culture (the Philosophy, Art, and Social Influence of games)
***Game Rooms and Archiving
***Off-Topic (topics not related to gaming)
Buy/Sell/Trade (open to people who have been a member for 30 days or more)
***Game Deals (post deals, brag about finds, etc. - open to all)
***Auctions (eBay links and general discussion of auctions - open to all)
Hacks and Mods
Sony and Microsoft
***Other Genres (RTS, FPS, Sports, Platformers, etc.)
There's a whole set of discussion on this topic here: viewtopic.php?f=15&t=15685&st=0&sk=t&sd=a
And that's not the only thread we've kicked around ideas in...is there any reason we haven't seen them implemented previously? I know this is an "official thread" but seems that this topic comes up regularly, we all spin our wheels and come up with good suggestions and then....nothing.