err dude, why are you being so paranoid?
First and the foremost, no one pairs i3-2100 with a P67 motherboard. People pair it with H67 motherboard. P67 is for overclocking and i3-2100 is a non-overclockable processor. A good H67 motherboard which I feel is worthy of purchase costs 5.5k. There are el cheapo H61 chipset motherboards too available for 3.5k but I don't like them so I rarely/never recommend them.
Second, games DO recognize 4 cores. All the latest games are very well multi-threaded.
Best for you would be waiting if you want to. Just wait for mainstream 970G chipset AM3+ motherboards to arrive. They haven't arrived yet and will arrive along with Bulldozer. Currently, only high end 990FX AM3+ motherboards are available.
yes, from what I believe, AMD will be ditching AM3+ in favour of FMx - for Fusion APU. They have maintained backwards compatibility since a loong time if you ask me. Fair enough if they do so although they might not do so and release a simple CPU. No one can knows what AMD might do and no one knows what Intel might do. Intel might have a change of mind and get a new socket for Ivy Bridge. I also remember a time when people were expecting Sandy Bridge for LGA 1156 and the Core i* processors for LGA 775. Just buy the best what you can buy now or after 2 months.
I say, just go for i3-2100 + H67 and be done with it if you want to buy now. Don't bother with X4 955 BE.