It's being billed as "One-window web development," and from what we can tell, it looks pretty awesome. I only played with the demo briefly, so there's obviously a lot more to this app then you'll find here (Steven's blog is a good place to go for the full scoop).
First of all, the UI is beautiful. When first launched, Coda offers to import your Transmit favorites, which it did perfectly for me. It then "taped" each project if found in my copy of Transmit to the main window. To work on a project, just double click it and it "flips" into view. One more click logs into the project's remote files and displays them in the left hand sidebar. Select any file to begin working on it. Super easy and fast.
Coda retails for $99 (lower introductory rates are available for now) and requires 10.4 or later. Now if you'll excuse me, I really want to stop typing and return to playing with Coda.
Thanks to everyone who sent this in!