Micro$oft does some things poorly, and some things well. Historically, HTML editing has been one of their weak spots: just view the source code of any Word document after you've selected "Save As > Web Page" and you'll see what I mean. Third-party integration is another weak spot...from what I've seen (admittedly, from the outside) they tend to force others to adapt to their APIs, not the other way around (JScript, anyone?).
So it comes to me as a surprise that I'm actually recommending an MS tool that does both: writes HTML (XHTML even), and conforms to a third-party API. In fact, I'm using said tool at this very instant.
Windows Live Writer is a small-footprint (under 10mb) utility which allows users to post directly to their blog. "What's the big deal?" you ask -- and right you are to do so, since most blogspaces have fairly decent WYSIWYG editors, spellcheck, and the like. Well, since you asked, here is a quick feature list:
- offline editing: no more trying (and failing) to cut-and-paste formatted text written while you were offline; edit in WLW on the road, then click "publish" when you're online again
- posts to all your favorites: Blogger, WordPress, LiveJournal, TypePad, Movable Type...
- multiple profiles: add each blog you edit as a separate account
- all the WYSIWIG HTML tools you'd expect: hotkeys and buttons to create lists, tables bold/italic/underline, links, etc; and the hotkeys are the ones you're used to from Word (CTRL-B for bold, CTRL-K for link, and so on)
- realtime spellchecking: yep, with the squiggly red line under your misspelled words (and if you hate that, you can turn it off). What's that? "Spellcheck" isn't in the dictionary? No problem...just right-click, add to dictionary, done
- insertion of images and videos (from your computer or the web): plus tools for varying borders, tone control, watermarking, and more
- drafts: automatically saved every few minutes
- templated insertion: set up HTML snippets, insert them wherever you like by selecting from a drop-down
- automatic hyperlinking: do you always link the word "google" to "http://www.google.com/search?as_q=google&num=100&lr=lang_en"? Add it to your link glossary, and WLW lets you pick it from a list instead of retyping the URL each time
If these features interest you, grab it from http://www.windowslive.com/Desktop/writer -- but don't forget to uncheck all the other checkboxes (like Messenger and Silverlight) when you run the installer, to avoid also adding lots of other M$ B$ to your machine...