Why wait 3 months? The Z68 is out now, and so is the P67. If the deciding point is $$$ then the P67 are slightly cheaper than the Z68 because they have a more limited chipset which doesn't provide for video switching or disk caching HDDs to SSDs.
The decision is yours but if you don't intend to cache a large HDD to a SSD and don't do video encoding then the P67 is just fine, as long as you bet the B3 revision.
I would need more info to help you make an intelligent choice.