Agreed I'm waiting until at least the new year 2007. Then all software should be optimised and any teething problems will be ironed out.
I run the the new ProTools 7 LE on my Powerbook 15" with Digi 02 Rack.
It's grand and have no real problems, obviously cant use as many plugins as you can with a G5. Antares Auto Tune 4 on a load of tracks will grind it, but the solution is simple, just bounce the track once its how you want it and you don't have to use the plug in, draining cpu.
I sometimes if I want to be more portable use an Mbox with the powerbook and have recorded a few concerts. I love the PB 😀