Google's contact manager doesn't include built-in groups for Google Chat friends or for the people you follow in Google Buzz. Fortunately, you can easily create a group for the people you follow in Google Buzz using a clever trick found by Siegfried Hirsch:
1. Go to Gmail's contact manager and search for http://www.google.com/profiles. Here's the URL for the search results.
2. Select all the results, click on the "Groups" drop-down and then on the "Create new" option.
3. Create a new group called "Buzz".
This works because Google automatically adds each Google Buzz user you follow to your contacts list and also includes the address of the Google Profile. If you've manually removed Google Profile address or added Google Profile addresses to other contacts, the results won't accurately reflect your Google Buzz group. Obviously, the group won't update automatically when you follow/unfollow Google Buzz users.
Google could use a lot of information from other services to enrich Google Contacts: the photos you tag in Picasa Web Albums, information and links from Google Profiles, Google Latitude location, the most recent Google Buzz message, but that will probably happen when Google Me is released.