in 2007 I complained that the Gmail Contact manager was sadly under powered. Happily it steadily improved and by the time the G1 phone came out it was really robust.
Today they finally spun it out of gmail and it’s now a standalone app. And at this point it’s pretty full featured. You can merge contacts, add tons of meta info, create groups. They’ve added everything I have wanted and now any new feature will just be icing.
The only complaint I do have is more about the G1 which currently has no built in use for the groups feature and I wish it did as it would be a little easier to find things without having to bust out the keyboard to search.