I'm finding more and more reasons to like Adobe's new AIR technology. They describe it as 'a new technology that makes possible exciting new software applications that merge the desktop and the web'; in practice, it opens software development up to those who chose to specialise in more 'creative' fields like Flash. And of course, because it's AIR, the same app runs on both Windows and Mac (with Linux support to follow).
Two current favourite tools: Analytics Reporting Suite, for looking at your Google Analytics data; and Twhirl, a lovely little Twitter app. In both cases, the originating website was already perfectly usable, but the convenience of a desktop app takes it a step further.
The Analytics tool is a reminder of the web's limitations, even in the post-Ajax world: it's just quicker, neater, and arguably prettier. And there are countless reasons to like Twhirl: you can log into several accounts at once; the interface removes the need to remember all those ugly Twitter codes; and there are 'toaster' alerts when a friend sends an update. Both are highly recommended... and free, obviously.