Hrmm. Tricky one, Kristine.
I'm tempted to point you to this article and leave it at that, but I think it's worth the time to revisit this question.
When you seriously think about it blogs are nothing more than a stripped down CMS (content management system). And, like all other CMSes, blogs enable you to worry about the design, the look and the feel only once (at the very beginning) after which you can ignore code and concentrate on your content. NYT online runs completely on Wordpress, and they only had to hire a designer, Khoi Vinh, once.
I suppose the 2nd thing blogs have going for them is the perception the Internet has towards blogs. Much of today's online recreational reading comes from blogs - I point to Dooce, Kottke, the hundred other online journals of friends and family that are read by a close personal circle. People come to blogs ready to read, to be entertained, and blogs are designed primarily to allow this recreational reading to happen. They have RSS feeds, for starters, making it way easier to follow updates to your blogs.
There's another argument, and this is Google related: blogs are far more search-engine-friendly than websites. Part of this is the way blogs archive your posts - the best way is according to date followed by topic title - and then there are tags. Entries with the right tags, which is really just another form of metadata, allow search engines to quickly categorize your content. I'm willing to bet you can do the exact same thing with a website, but it'll take up a lot more time and energy: apart from not needing to update every single page everytime I want to make a change, my blog has a sitemap and all I have to do is install a Wordpress plugin and click two buttons.
Granted, blogs are hard to get used to at first, and the code behind each system is unique and often hard to learn. But if you've got the time and the inclination, blogs provide unprecedented power to publish your content. And they're a lot easier in the long run as well.