...not to add more contrast in-camera, especially if you want to get the most out of the images the D100 can capture. Indeed, you might find it wise to LOWER the constrast in-camera to make sure you have the largest dynamic range possible when making the original image capture. You can always add contrast later in Photoshop, but you can never reel back in blown-out highlights and blocked-up shadows. The same kind of reasoning applies to in-camera sharpening. The Nikon digital pros suggest putting your camera on LOW contrast and NO or NORMAL sharpening (just enough to cancel out the anti-alias filter.) This way your digital "negative" will contain all the information it possibly can.
Now, if you just want a point-and-shoot camera mode you can change some things and keep them in bank B. But don't expect these images to be anything more than snapshot quality. My bank B shoots in FINE JPEG mode, AUTO sharpening, custom tone curve with a mid-tone lift, and NORMAL contrast. It's great for those snapshot moments, where I'm expected to give somebody a digital print, and I don't want the fuss of post-capture processing. These photos serve this need well, but I wouldn't prefer to make high quality enlargements this way. If you desire it and it suits your needs, you can put additional sharpening and or contrast (HIGH instead of CUSTOM for example) in bank B. You can also add color snap by selecting color mode III (enhanced sRGB). Experiment. If you think your camera underexposes for typical scenes you shoot, add exposure compensation as a routine matter. (Just like in a film camera, where I might always overexpose certain print film by 0.5 or 0.7 stop for additional shadow detail.)
But my most-used bank A is set to RAW, LOW contrast, color mode II and NORMAL sharpening. Images get tweaked in Photoshop to give me the highest quality image. The only change I might consider making is to take the sharpening OFF.
I am a bit amused about the "underexposure" problem reported by so many. After using the D100 now for about 6 months, I can confidently say that it behaves pretty much exactly like my N80 in terms of metering. Shooting digital is a lot like shooting slide film: you must avoid overexposing highlights at all costs. That often means erring slightly on the side of underexposure in high-contrast scenes, and that's exactly what the matrix metering system will do for you in the D100 in such scenes. For scenes of normal contrast, the D100 matrix meter system is dead-nuts on and uses the entire latitude of the sensor efficiently. You can always check your exposure with the histogram function which every D100 user should enable in the image review mode. If you're really underexposed, add 0.3 or 0.7 EV of compensation and shoot again. Those who are used to shooting slide film will understand the fussiness of exposure for high-contrast scenes. Those who have shot print film all their photographic life will discover when using the D100 that print film latitude covers a multitude of exposure sins.
Bottom line: if the D100 doesn't do what you want in the default mode, change it! The D100 has got more settings than a porcupine has quills, and it should be possible to get it to do something approximating what you want it to do. That's the beauty of a quasi-professional digital SLR. You have COMPLETE control. Use it to your advantage! My guess is no two users have the D100 set up the same way, and that is perhaps as it should be.