Best Gmail tip ever

I generally import all of my Gmail into my Outlook and read it there, but doing that leaves the messages "unread" on the Gmail server (which is especially annoying when I check mail on my iPhone). So, I periodically go into Gmail and clean it all up - labeling various messages, deleting junk, and marking messages "read". But it means that I have to scroll through pages and pages of mail, since some of it is already marked "read" due to various filters I've set up. I finally found a great trick to use to pull up just those messages that I need to address: in the text field above the mailbox, enter "is:unread" and click the Search Mail button. This will bring up only those "unread" emails.