Gmail added yet another
Labs feature, this time related to searching. If you enable "
Search Autocomplete", Gmail will try to finish your query using names and email addresses from your contact list, built-in Gmail sections like "starred messages" and more advanced searches like "has photos" or "unread messages".
The new feature is especially useful if your search includes
advanced operators like
to: or
from: because it's easier to enter the sender or the recipient.

Since Gmail doesn't show in the list of suggestions previous queries or common patterns from your messages, the feature has a limited use. You could get similar suggestions by typing names in the Gmail chat box and clicking on "View recent conversations".
Some other search-related Labs feature you should enable:
Quick Links, which lets you bookmark Gmail pages, including frequent searches,
Go to label, that autocompletes the name of a Gmail label, and
Multiple Inboxes, which allows you to create a dashboard from different Gmail views.
Another quick way to view your contacts is to use the standalone page for Google Contacts available at
google.com/contacts or google.com/contacts/a/domain.com. According to
the Apps Update blog, "the new standalone contact manager allows you to manage your contacts within Google Apps without enabling Gmail". You can also use it with a regular Google account that doesn't include access to Gmail.
{ Thanks, Niranjan and Jason Varitek Fan. }