If you're going to print your photos using a color managed workflow (properly profiled monitor, printing application supporting color management, profiled printer), then Adobe RGB is fine.
But, for posting photos on the internet for others to view, I'd suggest sticking with sRGB.
The problem is that most users have browsers that are not color managed, and will not properly render anything other than sRGB.
Click on the "Profiles and Windows" menu option from this next link, and you'll see a page with two side by side images tagged with different color profiles. They'll look the same if your browser supports tagged images (but, they'll look different if your browser is not color managed).
Here's another page you can see images tagged and untagged in a variety of ways, using a mouse over and clicking on them (and note that you should see a difference with some of them, as the untagged images using other color spaces are not supposed to display properly)
Safari is a color managed browser, as are newer versions of Firefox (and 3.5.x and higher versions default that way). But, Firefox 3.5.x and 3.6.x only support version 2 icc profiles for now. For example, version 4 profiles will not render correctly, and you can see that looking at this page:
Internet Explorer versions through IE 8 are not color managed, and 2.x versions of Firefox are not color managed. Firefox 3.0 has that ability, but it's not enabled by default (although 3.5.x and later versions are). Now, there is an addon that allows better control of it with Firefox here:
After it's installed, look under Tools>Addons>Extensions and you'll see the Color Management extension you just installed. Click on it's options button and select your calibrated profile.
I have it setup to use color management with all images. Under Advanced, I have it set to Perceptual.
It's my understanding that IE 9 will support color management. But, I haven't tried the IE 9 beta yet to see how well it works.
Bottom line is that most internet users are still not using a color managed browser. You'll also find that many image viewers and editors are not color managed (so if you e-mail an image to someone, the image viewer they're using may not render it correctly).
So, I'd stick to sRGB for sharing photos with others for now.