Patrix has a list of tools he uses for blogging. Once upon a time I used to use w.bloggar for composing my entries, but after starting to use multiple computers I gave up on installed software like Performancing. If you use multiple computers, then it might be worthwhile to look at Web Based editors and currently the one I am testing is Writley from Google.
While Bill Gates says that Wordpad has more features than Writley, it only means that he has never used it. Writley allows me to write articles as if I am in an HTML Editor, saves the document automatically every few seconds, and allows me to edit the HTML directly. It also has the ability to post directly to your blog. If you run a blog with multiple authors then Writley allows you collaborate on a document. It allows multiple authors to modify the same document in real time. You can have many versions of the document and revert back to a previous version or compare two versions.
Besides blogging, Writley can be used for storing your documents online. You can covert from Writley to doc, pdf and open office format. Writley, which is free, is now open for new registrations