1dsII & 5d noise
If you shoot jpeg the 5D looks smoother but that's achieved by heavier in-cam NR which sacrifices detail. The jpeg from 1ds2 has a lot more detail to work with at ISO 1600 and above. Also the auto white balance of 1ds2 is wayyyy better than 5D, if you are a jpeg shooter.
If you shoot RAW the WB is non-issue. At iso1600 and 3200 the digital noise of those two cams are very much the same at pixel level, because of the extra 4 million pixels you still get more detail out of the 1Ds2 shots.
overall the 5D is very good but 1ds2 is still king.