I just answered a Facebook Questions question about what blogging platform or tool small businesses should use. Here is the answer I provided
I personally use WordPress and recommend it:
1) Ease of use. (Not much more complicated than email or Facebook)
2) Flexibility (the back end interface allows you to adjust settings easily)
3) It has a great community of developers and creatives behind it.
4) Some Fortune 500 companies even use it (New York Times, CNN, Nikon, Nokia, Intell, Wall Street Journal, SONY Playstation, etc..)
5) The online support community is fantastic
6) If you host on your own domain–you can get a reasonably priced, but well designed theme which you can then customize.
7) In general the themes (templates) for wordpress are nicer than other platforms. For instance as a photographer or designer these premium themes at Smashing Webs are professional:
8) Local support through regional Wordcamp events.