Actually, if shooting in Adobe RGB matters, you've already dumbed it down a lot, because that means you're shooting JPG. If you're shooting RAW, color space is irrelevant - you can set it later.
You are right, I set mine to Adobe RGB but use raw, so it really made no difference. I use Lightroom 4 which has a prophoto gamut that is even wider.
I can do a soft proofing to my printer / paper profile and bring the colors into gamut as required.
You know, this has me thinking (a dangerous pasttime, I know...). I've often made the argument that the in-camera jpg settings do matter if you shoot RAW, indirectly, because the in-camera settings are applied to the JPG preview image that's reviewed on the LCD and used to generate the histograms. So, to the extent that you make exposure decisions based on the preview image, histograms, or blinking highlight alert, those JPG settings matter.
I wonder...what is the gamut of the camera's LCD, would sRGB vs. Adobe RGB make a difference in color channel saturation, a difference in the histogram or highlight alert calls, etc.?
I do not notice any difference in the preview for any color difference. I have a Pacific Blue Tang in my saltwater tank and when I take shots of it with sRGB the color is awful off it looks purplish not blue. With AdobeRGB it blue. The tang still shows up purplish in the preview. Clipping is a good question though.