The just-released Mailplane 2.1.6 from Uncomplex adds built-in support for the highly interesting Rapportive plug-in (see "Rapportive Plug-in Replaces Gmail Ads with Sender Info," 27 March 2010). Mailplane 2.1.6 also now works with the Share > Send via Mail menu items in the iWork '09 applications. With them, you can email your document via Mailplane in its native format or as a Word, Excel, PowerPoint, or PDF document. A few minor bugs have also been fixed, some of which were related to Gmail changes. ($24.95 new, free update, 6.7 MB)
Two Shortcuts for App Exposé
If you want to see all the windows for a particular app via App Exposé, there are two hidden shortcuts. For either, start by pressing Command-Tab to bring up the app switcher. Then, while still holding down the Command key, press either the 1 key or the up arrow. That puts you into App Expose mode, with all of an app's windows showing, and recent documents in a row across the bottom of the screen. Let up on the Command key, and then you can press Tab to cycle through all the running apps.