I just recently discovered the power of client-server API's for blogging. Three of the popular standards are Metaweblog, Blogger, and MovableType.
Sweet applications like Windows Live Writer utulize these API's to interface with your blog software. It seriously makes posting blog entries easy peasy like lemon squeezy.

Screenshot of me composing this post right now!
I can't agree with my friend DustyD more about web-based text editors like the FCKEditor and the FreeTextBox for composing blog entries:
I know I'm constantly making excuses for not posting that often, but I think that one of the major issues was my absolute HATRED for web-based WYSIWYG editors (FTB, TinyMCE, FCKEditor, etc). They're clunky, and slow and I just generally don't like them.
Word and 'nuff said!