Fast, efficient, usable and with great built-in search, Apple Mail is widely regarded as the best email client for the Mac.
But with some add-ons welded to it, Mail is even better.
Our top five plug-ins are listed below, and (perhaps surprisingly) we had them all running simultaneously while writing this, without Mail bursting into flames!
1. Mail.appetizer (donationware)
Mail's Dock icon badge updates when new mail arrives, but you have to switch to Mail to read it. Mail.appetizer uses a semi-transparent, configurable window to provide at-a-glance notification of new mail.
Mail.appetizer's appearance can be amended, as can what information is shown (headers, mailboxes, quotation levels, and so on). Despite permanent 'beta' status, Mail.appetizer is rock-solid and any Mail user that doesn't install it and bung the developer a few bucks is a crazy person.
One exception: if you're a Growl fiend, you might prefer GrowlMail (also donationware), which offers broadly similar functionality.
NEW MAIL: Mail.appetizer provides a configurable notification window for when new email arrives
2. Mail Act-On ($24.95)
Mail's Spotlight search makes filing messages somewhat redundant, but chances are you still have archive folders lurking in your sidebar. Mail Act-On enables you to file messages (and apply rules) without leaving the keyboard, via a combination of single-key triggers and Spotlight-like filtering.
Users of MailTags also get single-key triggers for adding keywords and setting projects.
EASY FILING: Mail Act-On enables you to file messages via keyboard triggers and filtering
3. Letterbox (free)
Many email clients offer a three-column view (folders/messages/preview) and widescreen monitors are increasingly popular. Therefore, Mail placing previews below the message list might irk, especially if you're switching from Windows or Entourage.
Letterbox can move the preview pane to the right of the message list, and there's an option for alternating message list row colours. The icing on the cake: the Mail plug-ins manager that's provided on the Letterbox disk image.
THREE'S ALLOWED: Get a three-column interface and a stripy message list with Letterbox
4. Mail Attachments Iconizer ($14.99)
Mail has definite ideas about how to display attachments, which can in rare circumstances lead to the app locking up as it attempts to render PostScript documents, or sending mail that a receiving client can't properly deal with. To be fair, said clients are usually old or buggy, but still...
Mail Attachments Iconizer enables you to switch between Mail's default handling, the plug-in's opposing settings (icons for attachments, bar those that are part of a message's body), or a user-defined mix.
TWEAK ATTACHMENT BEHAVIOUR: Override the way Mail deals with attachments with Mail Attachments Iconizer
5. MiniMail ($9)
If you'd prefer something more permanent than Mail.appetizer previews, MiniMail provides a resizable iTunes-like mini-controller when Mail is zoomed. The window has a bunch of handy controls and shows previews of incoming mail; usefully, said previews can be restricted to user-defined mailboxes.
MiniMail is keyboard friendly, enabling you to use cursor keys to navigate previews and standard Mail shortcuts to perform actions. Finally, borrowing from Quick Look, hitting 'Space' loads the currently previewed message in a HUD-style window, meaning you rarely have to return to full-size Mail.
HANDY SHORTCUTS: MiniMail apes the iTunes mini-controller, but provides plenty of shortcuts and a full-message preview