It's hard to imagine gadgets nowadays not looking disgustingly 1999 with colors, but we're talking about Apple here.
I'm confident that if they returned to using colored exteriors, they'd do it like most others wouldn't.
However, it's pretty hard to imagine the use of color without it looking horribly dated 2 weeks after the gadgets' introduction.
I look forward to eyeballing whatever they release, but until then, I'm still smitten with my 12" Powerbook. I think...