I'm surprised nobody mentioned Squarespace (http://squarespace.com/), popular for portfolio sites but also good for blogging, and really powerful suite (not free, though).

A geekier alternative is Calepin (http://calepin.co), amazing concept: you write your posts in multimarkdown, in a Dropox folder, and you publish by clicking a button that automatically checks that folder for new stuff (no template customization yet but Disqus integration). I am seriously thinking about switching to Calepin, Tumblr feels heavy on the browser.