I'm not an expert, but sRGB setting should be the one that best aproximates the official sRGB color definition. It shouldn't cause more problems than any other setting (like 6500 K). Here is wiki entry for sRGB:
6500K should be the default and is actually required by Microsoft these days to get Vista certification.
6500K tends to have more red, 9300K more blue and sRGB is like 6500K with lower brightness settings.
Custom Color is the native color temp of the panel and should look best. Depending on panel, it may be the same as 6500K as is the goal of the panel mfr's..
Having said all that, each to his own as not everyone's eyes are created equal. What I would do is this:
1) Make sure you're at the native 1680x1050 60Hz resolution.
2) Run Adjustment Pattern.exe utility that came on CD and select 'Factory Reset'. This will perform Auto Adjust function at same time to optimize clock and phase settings.
3) Select Custom Color.
4) Locate 32-bar grayscale pattern and then adjust Contrast so that you can distinguish between all bars.
If you can't find grayscale pattern, then download HP LCD First Aid utility, it has one in there somewhere. Do a search at HP.com website for it.
5) Next thing to do is to adjust the white point to your preference and it may be a good idea just to leave up the grayscale pattern.
If the white and light grays look too red, then open Custom Color OSD and tweak down red a few points, same with blue. I tend to prefer a little more blue myself because it softens the grays, but not too much. Too much green dulls your white point and makes your blacks look more gray. This gives a washed out look as well. You can verify your adjustment by just opening your browser window.
Enjoy you big monitor.
Sorry for the delayed response.
Leaving it in sRGB is not a problem. It's one of three pre-set modes for you to use. If you'd like to change the colors on your own then you can go to Custom Color and adjust Red Green Blue gains individually. Then you can go back and re-adjust Brightness and Contrast to your liking. Remember Brightness controls your backlights. Think of it as controlling your background. You can wash out your video if set too high. Contrast should be good around 80 - 85 range. If you go too high then you'll saturate the image. Basically your gray's go white and it's hard to distinguish between your higher gray tones.