Quick Gmail hack. Now you can set up Gmail to go to the older or newer email when you delete or archive an email.
To get started with “Auto-advance” go to the Labs tab in Settings, enable it, and click the “Save changes” button. By default, “Auto-advance” will advance to the previous (older) conversation in your inbox -- perfect for people who read their newest mail first. If you usually read your oldest email first and would rather advance to the next (newer) conversation, you can change the direction from the General Settings tab.
New in Labs: Auto-advance to the next conversation - Official Gmail Blog