For gaming, I'd agree with the majority of people and I'd say get an FX. But they are going to outdate themselves very quickly with the gaming industry taking on the dual core technology. But if your onsidering to buy an FX, surely you have enough money to buy a 4800?? I thought the FX series started at the price range where the X2s finish??
Also, about the M2 motherboard, I'm afraid to say I disagree with jac006. Basically, it opens up the AMD world to DDR2, which is great in itself, but the equivalent to DDR400 in DDR2 models is DDR2 667. Now that might not mean much, but to get the same performace as the DDR400, you're looking a big price for that RAM. Especially if you're wanting to upgrade to a great system (i.e. 2Gb of RAM) because it will set you back a fair few pennies.