On one side, i believe the quality of the S3 pics, with the wider DR, is -yet- unbeatable... but the camera is slooooooow on writing on the card, and generally doesn't allow fast use, like a D2H for example !
On the other side, the D2X is almost double the price, but is considered as a "pro" body... but i read quite a few posts mentioning problems with it !
In any case, i'm not in financial conditions now to buy one or the other, so i think that i'll pass and wait for an "even better" S4 or D3X !
In the meantime, i enjoy very much my S2, and frankly, as the largest print i ever make is A3+ (13" x 19"), i'm not really sure that i would see a tremendous difference in quality with the newer cameras !?!