The S5 is basically a D200 with Fuji innards and a different ( 6mp) Super CCD sensor. It doesnt have the same image processing or buffer capacity as the D200. It is geared towards tonality and color over biting sharpness or speed and was favoured for portraits or Wedding shots.
Not sure if its a good deal swapping the D80 for the S5 and think how that super sensors image processing will affect your shooting. On a good note, the S5 jpegs straight out of the camera are supposed to be second to none!
Would I have swapped my D80? No.
Allan