There is no reason why the shutter lag on the D100 shouldn't be similar to the N80 (or your N60). Keep in mind that the total shutter lag in AF cameras includes the time to achieve autofocus plus the time required to meter, stop down, flip mirror, etc. The reason for the extended shutter lag in compact digicams is because of the slower autofocus mechanism. The D100 uses the same AF module as the N80, so expect similar performance. Compact digicams and and SLRs have similar shutter lags AFTER FOCUS IS ACHIEVED, and this is typically in the 25-50 millisecond range.
I will be adding a D100 to my N80 when it is available. It adds capability that you can't get with an N80 (frame-by-frame adjustable ISO and white balance, immediate review, one-step image digitization) at the cost of some tolerable disadvantages (slightly less intrinsic image resolution, 1.5X field-of-view crop, limited battery life). I'll still be keeping the N80 and film, but expect to utilize the digital medium more and more. Digital is not better or worse, just different. Think of a D100 as an infinite supply of Fuji "Digia" complete with all the quirks and flavor as in traditional films. I'll miss all those extended evenings scanning slides and despeckling images. (Probably replace some of them with CCD-dusting sessions.)