I need to declare a winner in the race for my heart. The contestants are those popular social bookmarking sites (del.icio.us, diigo, reddit, digg, etc.), and they are all racing to be number one in terms of usefulness.
But I think the winner is del.icio.us.
Despite its insipid name, I like del.icio.us. It's got a clean and simple format, it's easy to use, and it's fairly robust. It has a large enough user base that I can cull and glean useful or interesting facts from its social side, and it's relatively painless to use as a bookmarking service.
It has another advantage: because del.icio.us is so widespread and simple, other services can be made to work in conjunction with it easily. Diigo, for instance, has easily imported all of my bookmarks, and allows me to double post them back into del.icio.us.
The problem that I have with social bookmarks is that I have no pressing need for them. I am fairly competent at storing my own information and finding new information without an explicit network of friends to help me. I already know where I can find garbage content to sift through to find useful things. If someone wants to share a link with me, I'll get an e-mail or an IM. That minimal level of entropy is enough of a filter for all the garbage they are looking at, I'm willing to accept that lose of an occasional LOLcat picture that didn't get forwarded my way.
So for being low on cruft, but high on content, del.icio.us, I choose you. But we've got to do something about that name.