After switching to mail.app from Thunderbird, the blogger at 48-Hour Days found that that she (or he) couldn’t live without Thunderbird’s F8 keyboard shortcut for showing and hiding the Preview Pane.
As everyone knows, you can show or hide it in Apple Mail by double-clicking the small dot in the separator between the Mail Viewer and the Preview Pane — Apple’s Technote 
shows you how.
But if that is not quick enough for you, 48-Hour Days provides an applescript that will automate the process and which can be bound to a Quicksilver trigger or FastScript’s shortcut.
Only hardcore keyboard fanatics will want to use this, but there are people like that out there, and this post is for them.
Reo-2007 has written a theme to give Thunderbird the “leopard Mail look”. This is the first Leopard Mail skin I’ve seen for Thunderbird, although others exist to give Mail.app the 
Thomas McMahon has knocked out some styles for the “Stylish” CSS-extension that produce brighter, better looking labels in Thunderbird. 
Four months ago, Nick Kreeger announced 
Michael Tsai has released an updated version of his spam-catching utility, SpamSieve, which adds support for Thunderbird and many other improvements.
Chris Landon emails with a reasonable request, something you don’t miss or even think about until someone else mentions it. 
The next best thing to Mail.app is a copy of Thunderbird skinned to look like Mail. At least, that was clearly the case until 
