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)
Disable Caps Lock
If you find yourself pressing the Caps Lock key accidentally as much as I do, note that you can disable it entirely in Mac OS X. Open the Keyboard & Mouse preference pane, click the Modifier Keys button, and in the dialog that appears, select No Action from the Caps Lock pop-up menu. You could remap it to another modifier instead, but that might make using differently configured Macs more difficult.