For those of us who nerd out about things like desktop wikis, VoodooPad 5 (from the creator of Acorn) is an exciting release. It brings new capabilities so powerful that they should come with a "for good, not evil" warning.
If you're not familiar with VoodooPad, it's a desktop wiki with media embedding capabilities, a scriptable interface and a lot of power under the hood. Whether you want to use it for note-taking, project management or even maintaining documentation and live websites, it's a powerhouse. We may have mentioned it once or twice before.
What's so great about version 5? First, Dropbox sync is greatly improved. You can even share docs with multiple people and see who edited what, when.
For those of us of the Markdown persuasion, there's a new page type specifically for Markdown, with editing features and syntax highlighting.
If you build large documents -- say, a documentation project for your software -- you can publish the entire document as a PDF or ePub book. There's a new feature called "Collections" that lets you create tables of contents and determine page order, which makes the export features much more useful for more linear output formats.
We've always been able to do fun things like write event scripts that search for certain @tags and compile them, but the new To-Dos palette offers a faster, customizable solution for this.