With Sparrow 1.2, the email client gains connections with Facebook (for displaying friend pictures and adding friends from within Sparrow), a unified Inbox, support for Gravatar, Subject-based threading, the option to create a new message by Control-clicking Sparrow’s Dock icon, and localizations in eight languages. A variety of bugs have been fixed as well. I still can’t consider Sparrow as a usable Gmail client due to its newest-first conversation sorting (so threads must be read from the bottom up) and extremely slow load performance for message bodies. A free Sparrow Lite works with only a single Gmail account. ($9.99 via the Mac App Store, free update, 11.9 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.