I have the same dilemma, and I've decided to try to wait it out for the Athlon4 and the nForce or KT266A motherboards to appear. I figure I'm going to be stuck using the MB and CPU I buy for at least 2 years, so I might as well get the ones I want.
Last I've heard, the MB's are due end of Sept, but the Athlon4 isn't until the end of October

I don't know if thats when they're expected to appear in stores, or just to be formally unveiled (yikes! that would be bad news!) If it's going to take more than a month extra from when the hot new MBs are out to when the new Athlon4 is out, I might just grab a 1.4 TBird (although maybe the 1.2 MP might be worth considering).