A lot depends on the type of sensor in the camera one strategy is not the same for another if its a CCD or CMOS sensor digital has less noise evident tahn film, when you blow up and image to A4 and above and it is just as true with digital that a lower iso gives finer grain/noise than high settings.. Very few sensors do a good job above 400 There may no longer be the same chemisty going on as I had with film trying to get the best balance is the key.. Perhaps another topic is the slower lens speeds these days I would like an f1.8 500mm lens please I am sure I would have less problems with noise and keep my ISO down to 200 then.. I always found I got less noise with longer exposures rather than putting up the ISO

Danny O'Byrne  http://www.digitalartzone.co.uk/

"All the technique in the world doesn't compensate for the inability to notice" Eliott Erwitt