Like many others here, I won't buy it until I hear definitive confirmation that it is hackable/moddable. I only ever wanted a sex d***s and rock & roll simulator. TS2 is as close as you can get, at the moment, but it surprises me that an independant company hasn't produced a completely "adult" game in the same vein (I don't count singles as it was rubbish or any of the virtual valerie clones (yes I'm that old)). It may be a weird thing to say on a Sims forum but the whole school/work/life micro-management part of the game (basically 95% of it) holds no appeal for me. The idea of coming home after a hard day at work and thinking "I know, I'll play a game in which the characters spend most of their time at school or work and a lot of their free time being instructed to perform basic life skills somehow never  struck a chord. Then I discovered hacks and mods and cc and never looked back. The free time ep is probably my favourite but it still has huge flaws, the most obvious being forgetting how to do activities if you don't perform them regularly (how can you forget how to go hiking?) I think my ideal expansion pack would be Sims lottery winner or Sims Hugh Hefner (amounts to the same thing) as that's how I play the game anyway.
  It looks as though Eaxis might be gearing Sims3 to the new market of Wii and nds owners who aren't looking for anything too complex or, indeed adult, in nature. There's a big cash cow there waiting to be exploited.
  I have no doubt that, if the new game is remotely hackable then those clever bods who improve games on our behalf will have it  nailed soon after the official release. If it turns out to be uncrackable or the custom content has to go through some kind of morality filter then Eaxis can insert it in the orifice of their choice.  
  That said, there's a couple of things that I'd like to see in the new game apart from a lot more adult content which I won't go into here.
1) House keys. I don't know about you but when I meet someone for the first time I don't immediately invite them into my home or give them carte blanche
in the house when they do visit. Family members from teens onwards would get them as a matter of course but they could easily become part of the popularity or romance paths, in particular romance, as the giving of keys to a girl/boyfriend could be a precursor to the move-in proposal.
2)Much, Much, Much better Ai. If I leave my sims alone for a few seconds, they immediately start dancing as it's the thing they have most enthusiasm for. They'll then dance until they drop unless I intervene. Basic life skills (in teens onwards) and an ablity to "do something different for a change" should be built-in.
3)If you really want to do the school/work thing, then why not have that time pass quickly (as it does in the game if all your sims are doing it) but then have what free time you have pass at a more realistic rate. I'm not talking real-time here but, say, fifteen minutes real time to an hour game time so it doesn't take an hour to hold a phone conversation or use the toilet (you know what I mean).
4) More owner content in game. I know you can produce a custom playlist for the radio and, with some effort, play custom video on the Tv but it could and should be so much easier. A player like Vlc, which can handle pretty much any sort of media is only a few Mb in size and surely couldn't be that hard to incorporate into the game. Likewise with the stereo. As well as custom playlists, why not include internet radio? Might be a bit hard on those with older systems but, again, surely not that hard. It won't matter what sort of music either as the sims will use the same dance moves regardless.
5) Different dance moves.
    Sorry for the lenghty ramble. This is my first post here and the reason I don't post on forums that often is that I will go on and on and on without neccessarily sticking to the thread and this annoys some people.