Being new to blogging, I may be a little late to the game as far as blogging tools go.  However, a colleague of mine introduced me to Windows Live Writer and I have to say that I'm impressed.

Prior to Live Writer I was using the web-based editor in our blogging site.  It worked okay but still had all the common issues associated with web-based editors.  They WYSIWYG capabilities were limited; it didn't offer auto-save so occasionally it was possible to lose your post before it posted; it relied on an IESpell plugin for any spell checking (which meant that it didn't spell check in any browser except IE); and it didn't handle embedded objects like photos, maps, etc. very well.

Live Writer does a fantastic job of making blogging easy.  It works with nearly any blog provider and has built in spell checking; the ability to insert embedded objects easily; downloads your blog's styles and provides a "preview" and "edit" mode using those; and has a ton of other helpful plugins to make everything from entering code snippets to screen captures easier.

Overall it's a really solid product with a lot of great features that I would recommend to any blogger.