I never see these icons either, tucked to the far right following the email's subjects and even body text previews. It's good to spot the indicators fast, though, and Gmail provides an option to, indeed, spot them faster — if you read from left to right: moving their column to the left, in front of all the subjects.
See Attachment, Calendar Invitations and Other Icons Up Front in Gmail
Note that moving icons is currently not available in Gmail.
To move the column of icons — indicating attached files, calendar invitations, Buzz posts, chat conversations — in front of email subjects in the Gmail message list:
- Click the Settings gear in your Gmail.
- Select Settings from the menu that appears.
- Go to the Labs tab.
- Maker sure Enable is selected for Move Icon Column.
- Click Save Changes.
(Updated May 2012)

