I do have a B&W G3 400 and even with 512MB RAM and UltraWide SCSI, it does feel aged running OS X. It's FINE under OS 9.1, etc. The problem is that there's no 2D acceleration being done by the video hardware to speed up Quartz and its massive CPU demand. I am sure that this will be addressed in part by drivers on current hardware and in part by new 2D acceleration hardware on future boards (vector-based 2D GUI's are definitely going to start popping up--OS X is leading the way--so the hardware will come). BUT, for now and I think this will be the case on out till the end of the year and bit beyond, it will take more CPU power to get OS X feeling super snappy.
Remember tho--OS 9 feel faster true, but its cooperative "multitasking" system is bad and wrong. Bad and wrong and it's amazing it's been the way of things on the Mac for this long. (The original Win95 multitasking kernel was leaps and bounds ahead of what MacOS 9.1 offers as far as a robust kernel--sad but dead true.)
Anyway--my plan is to get a dual 733MHz G4 tower, which should exist by then. UNLESS there is a 1GHz+ G4 that is shown, in benchmarks, to tear up the dual unit for general OS X apps, in which case I'll get that unit. At that point (Jan '02, when I plan the purchase, from the Tyson's Apple Store!) my machine will be 3 years old. That's old.
But for laptops--I'm the wrong person to ask. I am either in front of a machine all day at work or in front of one of my machines whenever I want to be, at home, in the evening. I really don't have a need for a laptop. Especially since I carry an iPAQ PocketPC around with me for a bit of portable utility. So as far as motivations that go into the purchase of one, you'd need to make your own call. I like the coolness of Apple's laptops (I see little in others' offerings) but prefer the power of the desktop units, which are going to have faster video, a faster bus, etc. Sorta like the Cube--it's crazy fine to behold, but the (aging) tower design simply allows more power and certainly expandability (who would use a computer with just one video card and monitor, for instance?).
Anyway -- just some thoughts.
blakespot