Trikstaa: he needs to know that nothing looks better than the Native Resolution. I mean, go ahead and compare for yourself. When an LCD monitor is at its Native Resolution, it's at its clearest and sharpest. But when anything other than the Native Resolution is used, then it begins to get blurry.
I have a friend who bought the same monitor I have a couple of months ago (the 22" widescreen Samsung 2253BW). His previous monitor was a 17" CRT, and he used 1024x768. When he first started using the monitor, he absolutely refused to use the Native Resolution of 1680x1050 because "everything was too small" and then picked something like 1280x1024. So, I explained why the Native Resolution was the best option. I then showed him the difference between the Native Resolution and any other resolution. However, he said he didn't care and still insisted on using something else so that everything was big enough. But, while he was alone for the first week, he eventually tried using 1680x1050. As soon as he tried it, he called me up to thank me for telling him about it because now everything was much better looking and now he refuses to use any other resolution. To this day, he's still using 1680x1050. He sometimes still raves about how much better looking this resolution is.
So, try to convince him to use the Native Resolution. The monitor was designed to look best at that resolution anyway. Not only that, but the monitor is so big that the native resolution won't make things that much smaller anyway.