The 1.33Ghz 12" iBook I just bought does everything I need, so I won't get another laptop unless it is substantially better in certain key ways. If one like that were to appear tomorrow, I might wish to get it on account of those vital features, but money is tight at the moment... another reason to get it would be that if I need my current iBook to be serviced, I don't want to be without a laptop for any period of time... so that would be an issue of money. Otherwise, here is what I'd need to buy another lappy from Apple:
1) All things being equal (i.e. not worse feature-wise than the current iBook), if it was 3lb, that alone would make me buy it.
2) All things being equal, if the screen were substantially better (brighter), 13" or bigger without greater weight, and without losing vertical lines compared to the current 12" - this is somewhat subjective (I'd have to see the screen).
3) All other things being equal, the battery life is 10 hours or more compared to todays 5-6 hours.
If at least one of the above 3 points are not fulfilled, then I'll ride this current iBook until the software is no longer supported, or I develop other needs (say desperate need to burn DVDs on the road), or this iBook fails somehow and either AppleCare or Amex Gold warranty can't fix it, or they decide to replace it with a new one (thus it's out of my hands).
The following things would be nice, but without one of the points above, these points below would NOT be enough for me to buy a new Apple lappy:
a) Faster - like, much faster - so that I do not have to suffer through the frequent pinballs
b) 2 firewire and 2 usb
c) BluRay superdrive
d)illuminated keyboard
e)iSight
f)hibernation
g)all apps I use - intel native
h)better speakers and better sound card
i)right-click button on trackpad
j)RAM expandable to 2GB
k)better keyboard
l)better fit and finish on the case - no creaks, cracks, ill-fitting keyboards
m)runs cooler, and I almost never have to hear the fans even under fairly heavy load
n)200GB HDD standard
Obviously points a)-n) probably will apply to the 12" MacBook Pro one day soon, but call me crazy, there's one thing I much prefer in the iBook - yes, I like the casing better on the iBook - guess I'm in a definite minority... I think the aluminum is meh, while the nice white is way superior, plus, very, very important to me, the iBook is much sturdier compared to the current PBs... the aluminum dents way too easily and is too hot (transfers heat too much). For those reasons I'm not crazy about the casing on the PBs and the likely MacBook Pro... I'll prolly continue to stick to the iBook for that reason alone.
Finally, in all honestly, I don't anticipate that any Apple laptops (I won't even consider PCs), will actually compel me to switch to Intel within the next 5 years... when I do switch it'll prolly be for some mundane reason, like my current machine just broke down, it won't be because I'll be wowed by the features, since I don't believe the *to me wow* features I outlined (points 1, 2, or 3) will actually appear in the next 5 years. Of course something totally unexpected might happen, something so cool I just gotta have it