G5's won't be out for at least a year. They are having alot of trouble with cooling as dual processors heat up alot and the small case can't carry a large enough fan.

They are experimenting with NASA technbology for silicon cooling but the last I heard it wasn't coming along as they'd hoped.

And even when it does come out, much like the G4 powerbooks, the second round of releases will kill the first.

I say buy the powerbook or better yet go through flexirent and upgrade when the G5 is released.