Well, there's a subject! Here's what I've found - my Fuji S2 is great at ISO800 but a lot of times I need more than that for shooting bands. 1600 is the highest on the Fuji and it's not pretty - but I haven't tried any noise reduction software. Lately I've been using Delta 3200 exposed at 1600 when I can and 3200 when I have to. My film scanner isn't the greatest, and it will take some work to get decent results.

I'd probably not go with a D100 at this point - it's been around as long as the Fuji S2. The D70 looks pretty good at 1600 though. You also have the benefit of a histogram and LCD display to see if you're getting the results you want. And adjustable white balance so you don't have to worry about color shifts.

When the light is so low that I need 1600 (even with f1.4 lenses) then the AF won't really work too well on a D70/S2/D100 etc. Another reason I use film in that situation is that it's in an F5 which can almost see in the dark.