I'm personally going to be buying the last PPC revision of the powerbook to supplement my rev A G5. Then, I plan on purchasing a rev b intel mac.
I forsee many bugs in the rev a intel macs, and do not wish to be a part of them. Then again, if you're looking to get a PowerMac, there may not be another PPC revision before the switch... so either you are willing to deal with the possibility of numerous bugs, or want to get a reliable (but not as fast) machine.