>In the long run I would save about $100 a year in Film and >processing, more than making up the loss interest.
Remember that you're going to have to buy compact flash cards for the D100. And maybe buy a new DX flash, AC adapter, Nikon Capture 3, a digital wallet, MB-D100 grip, photo printer/paper/ink, etc. The accessories can easily add up to more than the $200 you're saving on film/development costs. If you plan to print, printing costs are a per shot cost rather than a fixed cost.
>The question is: is the D100 a professional camera with >professional results?
Depends on who's behind the camera.
>I like using my 24mm Nikkor and my 50mm Nikkor (not a zoom >guy at all). How much of a drawback is the 1.5X of the CCD >compared to 35mm film? Would my lenses effectively become a >37mm and a 75mm?
Yes. How much of a drawback this is depends on how you shoot. Can you live without wide-angle (or afford a 16mm lens)?
>Another question, with the fastly changing digital world, >would I regret the purchase after a couple of years when the >D200 comes out?
Again, this is a personal issue. The D100 will still take the same quality images 10 years from now as it does today. Will better cameras come out in the next 2 years? Definitely. They will be faster, better, higher-resolution, and cost the same or less as the D100.