I am using windows live writer more then a year for blogging. Its a great tool to blog the things. There lots of inbuilt features are there. Like you can insert videos,Format HTML, Insert hyperlink, insert picture directly from the desktop etc.
A new version of window live writer is having all this functionality. As well as its having plug ins that can be very use full when you are professionally blogging the things. There lots of plug in available like twitter update,dig this and flicker
As well as all this you can directly insert videos from YouTube,soapbox etc.
Here is the link for the downloading the windows live writer.