Randy
I just did this evaluation myself. I bought the S2. Here's why:
1) 12MP vs 6MP -- the S2 is "interpolated" but it's still 12MP
2) b&w capture -- I think that the b&w capture in the camera is better than desaturating in Photoshop. You certainly have to screw around much more with a desaturated image to make it the right balance of tones and contrasts.
3) Color -- I think the Fuji electronics have better color than the Sony electronics in the D100.
4) PC synch -- the S2 has one, the D100 doesn't
5) batteries -- the S2 uses AA, the D100 has a rechargable. You can always pay the extra $200 and get the grip for the D100 that takes AAs. I like having AAs cause you can't recharge a battery on top of a mountain with a three mail hike back to the car!
Actually that's one advantage that the D100 has -- the battery grip has a vertical shutter release. Nice feature.
The bodies are the same -- in fact the D100, S2 and 14n are all the N80 body.
Any specifics feel free to post 'em or shoot me an e-mail!
Bob