Another question from me,
I need a real-life answer here, will a 1.67GHz Powerbook with 1GB RAM and a 9700 128MB handle all of the special effects that tiger can offer (ripples, dashboard widgets, etc etc) properly and easily WHILE using the computer properly for example with photoshop open?
previously my performance question was on hardcore-multitasking, now its narrowed down to that but with sfx.

Without a doubt. That would be nearly a top of the line PowerBook.

thanks
its what I am planning on getting
I am going for a seriously-future proof powerbook.
I want long-lasting power with mobility, so its a powerbook-powerbook choice:P
I guess an imac might offer better future proofing, but i really want to be able to like, sit ant my desk for a while, but then when i feel lazy, go and lay on the sofa but still be able to use my machine properly:)

Yes, it will. I have a 1.5GHz (12") PowerBook with only 768MB and it is pretty fast (that is, without PS running since I don't use it). Your one should be fine.

I think tiger need much more ram than panther, when I used panther, I have 500-600 mb free ram, since I used tiger, I only get 100-200 when I am doing the same project with same amount of app active (photoshop, dreamweaver, bbedit, terminal etc), so I think if you can get 1.5 gig ram, just in case.

I think what you are seeing is the difference in memory management between Panther and Tiger. Panther would page things out to the hard drive much too quickly, Tiger doesn't do this as much, which means it's actually taking BETTER advantage of your free RAM.