Use Mail Perspectives to create a compact Perspective window for each of your critical mailboxes. Use the All/New/Today bar to tailor which messages they will show. Whether you want to see the latest message or the recent message list, Mail Perspective's compact window design means your email can always be visually available, but never the focus of your attention until you need it.
Mia for Gmail (was Notifier Pro for Gmail) is a desktop Gmail client which sits politely in your menu bar.
