Mac OS X’s default mail browser, Mail.app, is a pretty straightforward e-mail client with a few bells and whistles. But for those coming across from e-mail clients such as Thunderbird or Outlook, especially from daily workflows that revolve around e-mail, they may find the out-the-box functionality a little lacking. Cleverly Mail.app is easily extendible using a plugin-in interface, so you can just simply add the functionality you require. The list below are my minimum requirements to make Mail.app workable. All are free in one respect or another. Your mileage may vary.

WideMail

http://www.daneharnett.com/widemail/

Why waste screen real-estate on a widescreen laptop monitor with Mail.app’s preview pane situated below your mail list? This plug-in switches the layout to three vertical panes: mailboxes, mails, preview which makes much better use of the available space.

Mail Badger

http://www.tonyallevato.com/node/1

This is infinitely useful you have mail coming in from multiple sources, or want to keep track of specific incoming mail, etc. It replaces the in-built badge functionality and lets you create little badges on your dock icon to count mail based on user-defined rules. Absolute brilliance. As an example I use one rule to count the number of mail coming from known client addresses, and another to count mail coming from my social networks. One I have to keep an eye on, the other is just there for my own interest.

Caius – points out that there’s an alternative to Mail Badger in Dockstar. Unlike Mail Badger, Dockstar is a paid for application and offers greater display options than Mail Badger. Mail Badger also occasionally throws a wobbly and causes Mail.app to crash. I’ve not heard anyone report this same behavior from Dockstar.

SignatureProfiler

http://www.littleknownsoftware.com/sigpro/

Pretty straightforward, multiple identities, multiple signatures. Mail to clients does not warrant the same signature as mail to friends. This functionality should really be built into Mail.app itself but there you go. SignatureProfiler remedies the situation elegantly.