Dennis said:
I use aRGB when I am going to do a print and sRGB when posting on the web
In the past I did some comparisons using AdobeRGB and a custom profile in Q-SE raw processing. Just recently I did the same with sRGB and a custom profile and then converting the custom profile version to sRGB.
The difference is significant in my view, thus demonstrating the advantage of using a custom profile, even for web publishing.
Two versions of a sample image are shown below.
RAW processed with Custom profile converted to sRGB
RAW processed with sRGB
You can see more comparisons here:
http://www.pbase.com/tjm04/compareiccTerry