Which blog-writing software should I use?

I want to start writing a blog instead of sending an occasional newsletter to contacts in my field. Ideal software would be somehow situated on my domain to help increase traffic to my site, easy to start/“install” for a non-techie, easy to post including from my iPhone, complete with helpful features such as future posting, simple/attractive look, and easy for people to find via search. Any ideas? (I’m drowning in all the blog info out there.)