Brewster
This summer I've been working in New York City at a startup called Brewster. Brewster is "your personalized address book." Basically, you link it with any and all -- I recommend all you have -- among your facebook, twitter, gmail, iPhone contacts, linkedin, and foursquare, and then Brewster gathers information from all your services, brings it into one place, makes it look really pretty, and let's you manipulate it, search on it, and organize it exactly to your liking. Best of all, it's just for you, so from a privacy standpoint there aren't the worries that you have with social networks and stuff.
Anyway, we just launched this morning, and I invite anyone who stumbles upon this page to check it out and share it with friends. So far the initial feedback has been really nice, and if you're interested in reading more about it, here are some links to what people have been saying.
Hope you like it too!