If Gmail's UI floats your boat but you prefer using a desktop email client for 'no waiting for a refresh' feel, Ken Mixter has developed a Thunderbird extension just for you. The GmailUI extension brings many of the shortcuts and search expressions of Gmail to Mozilla's Thunderbird client. Keyboard shortcuts like J and K for moving up and down through messages, as well as search expressions such as 'subject:' and 'from:' can now be a part of your Thunderbird experience. Ken even went so far as to include Gmail's 'archive' functionality and (oddly) a quick calculation function, right from within Thunderbird's search box.
The extension appears to be completely free, and Ken is accepting feedback and suggestions at his site
. Head over to Mozilla's addons site
to grab the extension, or check out Ken's site for a lot more details of everything GmailUI is capable of.